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Cameline filarosis is an important parasitic disease having an economic impact on the camel industry around the world. However, there has been no study on filarosis in Bactrian camels of Mongolia. Therefore, the aim of the present study was to detect and identify microfilariae of Deraiophoronema evansi (D. evansi) in Bactrian camels from three provinces, located in southern and southwestern Mongolia. Blood samples were obtained from 400 healthy two-humped camels of different ages and both sexes. All blood samples were analysed using a variety of diagnostic techniques. Microfilariae were detected in 30 Bactrian camels (7.5%) by the Knott technique, while 13 Bactrian camels (3.3%) tested positive in a direct smear test. D. evansi was detected in 18 Bactrian camels (4.5%) by PCR assay. Prevalence was shown to be high among Bactrian camels in the age group up to 5 years, while the lowest positive results were obtained for Bactrian camels in the 5-10-year age group and the over 10-year age group. To confirm the morphological identification, D. evansi-COI gene sequences were subjected to phylogenetic analyses. The D. evansi-COI gene sequences from Mongolian two-humped camels were identical to sequences from Iranian one-humped camels and were clustered together with these sequences in the phylogeny. This is the first report of molecular detection and identification of microfilariae of D. evansi in Bactrian camels of Mongolia., (Copyright © 2021 Elsevier B.V. All rights reserved.)

Six Dipetalonema species have been reported from Neotropical monkeys, Dipetalonema gracile, Dipetalonema graciliformis and Dipetalonema caudispina being the dominant species found in French Guiana primates. Adult filarioids isolated from the abdominal cavity of tamarins (Saguinus midas) in French Guiana were morphologically and molecularly identified as D. graciliformis. Phylogenetic analysis based on DNA and amino acid sequences of the cox1 gene as well as the concatenated sequences of the cox1 and the 18S genes indicated that D. graciliformis belongs to the clade 4 (ONC4) of Onchocercidae. Blast analysis of the 18S rDNA revealed that D. graciliformis in the studied tamarins is conspecific with the filarioid circulating in howler monkeys (Alouatta macconnelli) in French Guiana, previously referred to as unidentified Onchocercidae species.

Dipetalonema caudispina (Molin, 1858) and D. gracile (Rudolphi, 1809) (Filarioidea: Onchocercidae) are two of six known species of filarial nematodes that parasitize Neotropical non-human primates. Adult filariae were collected from the thoracic and abdominal cavities of 38 of 44 specimens of Sapajus macrocephalus (Spix, 1823) and nine of ten specimens of Cebus albifrons (Humboldt, 1812) (Primates: Cebidae), distributed in the Yavarí-Mirín river basin and used locally for human consumption. Co-occurrence of D. caudispina and D. gracile is reported for the first time, with a prevalence of 18.5% (10 of 54 hosts examined). Our finding of D. caudispina and D. gracile in cebids from the Peruvian Amazon constitutes a new geographical record for both filariae, two new host records for D. caudispina, and the first report of D. gracile in S. macrocephalus. In addition, we provide morphometric data for D. caudispina, complementing the original description, as well as scanning electron microscopy details on the structure of the area rugosa and number of caudal papillae in males.

Dipetalonema gracile is a common parasite in squirrel monkeys (Saimiri sciureus), which can cause malnutrition and progressive wasting of the host, and lead to death in the case of massive infection. This study aimed to identify a suspected D. gracile worm from a dead squirrel monkey by means of molecular biology, and to amplify its complete mitochondrial genome by polymerase chain reaction (PCR) and sequence analysis. The results identified the worm as D. gracile, and the full length of its complete mitochondrial genome was 13,584 bp, which contained 22 tRNA genes, 12 protein-coding genes, two rRNA genes, one AT-rich region and one small non-coding region. The nucleotide composition included A (16.89%), G (20.19%), T (56.22%) and C (6.70%), among which A + T = 73.11%. The 12 protein-coding genes used TTG and ATT as start codons, and TAG and TAA as stop codons. Among the 22 tRNA genes, only trnS1AGN and trnS2UCN exhibited the TΨC-loop structure, while the other 20 tRNAs showed the TV-loop structure. The rrnL (986 bp) and rrnS (685 bp) genes were single-stranded and conserved in secondary structure. This study has enriched the mitochondrial gene database of Dipetalonema and laid a scientific basis for further study on classification, and genetic and evolutionary relationships of Dipetalonema nematodes.

Despite the economic importance of camels, the parasites that affect them have not received adequate attention so far and molecular studies are scarce compared to other livestock. In this study, we characterized peripheral blood microfilariae in 200 healthy one-humped camels (Camelus dromedarius) from south-east Iran by microscopy and molecular tools to receive a more detailed insight into prevalence and species that affect them. Moreover, adult specimens of the filarial nematode Dipetalonema evansi were collected from the carcass of an infected animal. Microscopic examination was performed on Giemsa-stained blood smears, and blood was also spotted on Whatman FTA(®) cards for DNA analysis. Genomic DNA was extracted, and PCR was carried out for the detection of filaroid helminths, followed by sequence analysis of positive samples. Four samples were positive for microfilariae by microscopy, while 16 animals (8 %) were positive by PCR. Sequence analysis revealed D. evansi in all cases. Phylogenetic analysis of a cytochrome C oxidase subunit I (COI) sequence of filaroid nematodes showed that most species in a single genus cluster in the same clade; however, D. evansi and D. gracile are not monophyletic and branch rather at the base of the tree. Further studies on the life cycle of D. evansi, specifically the identification of intermediate host(s), have become feasible with the provision of the first specific COI sequences in this study.

Totally 294 dromedary camels of different ages and both sexes slaughtered at slaughterhouses in Yazd, Isfahan and Kerman provinces were inspected for infection with Dipetalonema evansi. Blood smears of all camels and carcasses of 125 of them (100 from Isfahan and 25 from Yazd) were studied for larva and adult forms of the parasite. Microfilariae were found in peripheral blood smears of 38 out of 294 (12.92%) tested camels, while 20 out of 125 camels (13.89%) harbored D. evansi adult worms in at least one region in their testicle, epididymis, spermatic cord, lung and heart. Two of infected males had adult forms of the parasite in all studied organs simultaneously. Pathological study of infected tissues revealed sections of parasite, severe acute and chronic inflammation, fibrosis and atrophy. D. evansi is endemic and constitutes an important health problem to camels in Iran's central desert, resulting in impaired working capacity and lowered productivity.

Background: Hippobosca longipennis (the 'dog louse fly') is a blood sucking ectoparasite found on wild carnivores such as cheetahs and lions and domesticated and feral dogs in Africa, the Middle East and Asia, including China. Known as an intermediate host for Acanthocheilonema dracunculoides and a transport host for Cheyletiella yasguri, it has also been suggested that H. longipennis may be a vector for other pathogens, including Acanthocheilonema sp.? nov., which was recently reported to infect up to 48% of dogs in northern India where this species of fly is known to commonly infest dogs. To test this hypothesis, hippoboscid flies feeding on dogs in Ladakh in northern India were collected and subjected to microscopic dissection., Results: A total of 12 infective larvae were found in 10 out of 65 flies dissected; 9 from the head, 2 from the thorax and 1 from the abdomen. The larvae averaged 2, 900 (± 60) μm in length and 34 (± 5) μm in width and possessed morphological features characteristic of the family Onchocercidae. Genetic analysis and comparison of the 18S, ITS-2, 12S and cox-1 genes confirmed the identity of the larvae as the Acanthocheilonema sp.? nov. reported in dogs in Ladakh., Conclusion: This study provides evidence for a potential intermediate host-parasite relationship between H. longipennis and the canine Acanthocheilonema sp.? nov. in northern India.

The Mediterranean monk seal (Monachus monachus) is one of the world's most endangered marine mammals. The largest population is located mainly throughout the Aegean and Ionian islands and along the coastline of southern continental Greece. We report the findings of a necropsy and discuss their potential importance to the conservation of the species. The adult female monk seal appeared to be in a good nutritional state. The main necropsy findings were injuries consistent with a violent and sudden death, including three round wounds on the ventral surface of the body and several hematomas, as well as a decomposing male fetus in the uterus. Two nematodes were found in the right ventricle of the heart; no abnormalities were observed in the lungs, pulmonary vessels, or heart. The nematodes were identified as Acanthocheilonema spirocauda. This is the first report of infection of the Mediterranean monk seal with A. spirocauda, even though this is the most common heartworm found in most pinnipeds worldwide. This parasite should be considered in health care monitoring projects of this endangered species.

The heartworm Acanthocheilonema spirocauda (Leidy, Proc Acad Nat Sci Philadelphia 10:110-112, 1858) Anderson, 1992 is described from material collected from harbour seals in Scandinavia and compared with types and other specimens described by Anderson (Can J Zool 37:481-493, 1959) from harbour seals in eastern USA. Most morphometric characters of the material from USA fall within the ranges established for the Scandinavian one. Some intraspecific variability in the organisation of papillae on the male tail was detected among the Scandinavian specimens. Differences between the specimens from Scandinavia and Eastern USA are also found in the organisation of papillae on the tail of males and females. An excretory pore was not discernible, but a clearly hemizonid-like structure is described. For the first time, scanning electron micrographs present external morphological structures of the species.

We describe a new species of Dipetalonema occurring in the body cavity of Ateles chamek (Humboldt, 1812) from north-central Bolivia. Morphologic characters serving to separate Dipetalonema yatesi n. sp. from known forms include a vagina vera with a simple tube and thin walls and a left spicule, which possesses a handle shorter than the lamina (ratio 2.7); the latter displays an anterior membranous alae similar in length to the terminal flagellum, a distal extremity of the left spicule within a simple hook and a membrane, phasmids at the basis of the lappets, and heterogeneous muscles occupying the whole cavity. Dipetalonema yatesi n. sp. can be separated from Dipetalonema robini, Dipetalonema gracile, and Dipetalonema graciliformis, between other characters, in having a simple vagina vera instead of a sinuous one, and from Dipetalonema caudispina and Dipetalonema freitasi in having the lamina of the left spicule divided in a membranous alae and a terminal flagellum.

Acanthocheilonema dracunculoides was diagnosed in 2 dogs from Windhoek, Namibia, by acid phosphatase staining of microfilariae. This is the 1st record of A. dracunculoides in Namibia.

Accurate diagnosis of canine filariosis is essential for choosing correct therapeutic approach. Therefore, reliable methods for discriminating among the different filarial infections in dogs are needed. The authors report simple and highly specific molecular methods that identify the three most common filarial nematodes of European dogs: Dirofilaria immitis, D. repens and Acanthocheilonema (syn. Dipetalonema) reconditum, based on (1) PCR amplifications of mitochondrial DNA (12S rDNA and coxI) with general filarial primers followed by digestion with restriction enzymes that generates band polymorphisms clearly discriminating the three species and (2) PCR amplifications with species-specific primers to support the restriction analysis, in particular in the case of multiple infections.

The present study determined the prevalence and geographical distribution of Dirofilaria immitis and other filariae, from dogs in littoral areas of Paraná state, in Brazil. This survey spanned eight months, between 1998 and 1999, and was also designed to compare the efficacy of different tests for diagnosis of heartworm infection in that area. Blood samples were collected from 256 native-owned dogs distributed along the Paraná coastal area. Five diagnostic procedures were used: direct smear examination, the Knott's modified test, filtration assay, and two heartworm antigen detection kits. A follow-up imaging exam was performed to support the heartworm diagnosis. The imaging diagnosis included radiographic and ultrasonographic exams of six dogs that had positive results for the heartworm antigen detection kits, but showed different microfilarial burdens. The presence and severity of radiographic and ultrasonographic signs were compared with the results obtained in microfilariae detection and antigen tests. Diagnostic parasitology results indicated that 31.25% of the dogs were microfilaremic. Three different microfilariae were recovered: D. immitis, Dipetalonema reconditum, and the third (mf3) was not identified. D. reconditum was the species with the highest prevalence: 22.6%. In general, D. immitis prevalence was 5.47% (28.57% occult infections), but it varied along the coast and the range was from 0 to 20%. No correlation could be established between the overall scores for microfilarial counts (small or large numbers) and the severity of radiographic results or the likelihood of detecting filariae in the pulmonary artery using echocardiography. The finding of a different type of microfilaria (mf) suggested the existence of a third species in Paraná state, whose prevalence was 4.68%. These results show that to obtain a reliable diagnosis of heartworm infection, antigen detection kits are indicated. Knott's test or filtration should be performed to confirm microfilaremia and not for diagnosis of heartworm infection. Imaging tests support parasitology exams and add more about severity of infection. The northern areas, specially Guaraqueçaba and Ilha das Peças, presented the highest number of heartworm-infected dogs.

Both Dirofilaria immiti and Dipetalonema reconditum may be found in blood of infected dogs but it is not easy to distinguish D. immitis from D. reconditum in morphology. We cloned and sequenced the contiguous internal transcribed spacer (ITS) region, ITS1-5.8S-ITS2, of these two different parasites and published on GenBank as AF217800 for D. immiti and AF217801 for D. reconditum in this study. We designed two pairs of specific primers derived from ITS2 being used for polymerase chain reaction (PCR). The amplicons of ITS2 from D. immiti and D. reconditum are 302 and 348bp, respectively. Moreover, the limitation for amplifying ITS2 gene using this PCR demonstrated that 1 x 10(-2) microfilaria of each species of parasite smashed or even with mixed samples could be detected and the PCR products were predicted as the same as that described above. Thus, D. immiti and D. reconditum could be differentially diagnosed by this specific PCR. Seventeen clinical cases were evaluated and all of them were correctly identified. In this study, ITS1-5.8S-ITS2 of D. immiti or D. reconditum were the first time sequenced and analyzed. No significant similarity of ITS1 and ITS2 between D. immiti and D. reconditum could be observed.

A dog microfilariae prevalence and risk factor survey was conducted in 51 contiguous municipalities of the Mt. Vesuvius area (Campania region, southern Italy) in order to add data to the limited epidemiological information available regarding filarial worms in this zone. Between May 1999 and June 2000, blood samples were collected from 351 asymptomatic dogs. Blood samples were examined using a modified Knott's technique and histochemical staining in order to count and identify microfilariae. The results were subjected to statistical analysis and choroplethic municipal maps (MMs) were drawn by a geographical information system (GIS) software. Microfilariae were detected in 63 of the 351 dogs surveyed, constituting a total filarial prevalence of 17.9%. In particular, 56 dogs (15.9%) showed only microfilariae of Dipetalonema reconditum; three dogs (0.8%) only microfilariae of Dirofilaria repens; two dogs (0.6%) microfilariae of both D. reconditum and D. repens and two dogs (0.6%) microfilariae of both Dirofilaria immitis and D. repens. High D. reconditum prevalence was associated with hunting practice, masculine gender and older dogs. There was also a tendency to find high prevalence in dogs sampled in the afternoon. In conclusion, the presence of microfilariae of D. reconditum in 92% of microfilaraemic dogs indicates that this filarial worm was the predominant filarial species in dogs in the Mt. Vesuvius area. In addition, the general trends of the MMs showed that D. immitis and D. repens were present only in a few municipalities, whereas D. reconditum was widely and homogeneously spread throughout the entire study area.

The diagnosis of canine heartworm infection is based upon the presence of circulating Dirofilaria immitis microfilariae or on techniques for the detection of serum antibodies or antigens. In the first of these, discrimination between D. immitis, D. repens and Acanthocheilonema dracunculoides microfilariae is based upon the acid phosphatase histochemical stain. In this paper, we propose an alternative technique for histochemical staining using a commercial kit test of naphthol-AS-OL (Leucognost-SP). This offers the advantages of speed and simplicity as compared to the standard Barka procedure.

A survey on the prevalence of Dirofilaria immitis and Dipetalonema reconditum was conducted in 1,519 dogs from Maceió and two coastal areas in the State of Alagoas, Northeast Brazil, from 1995 to 1999, by testing for microfilariae in blood. All blood samples were from exclusively domiciled dogs with a known history, showing that the infections were autochthonous, confirming transmission of canine filariasis in these areas. In Greater Metropolitan Maceió, 15 (1.3%) microfilaremic dogs were detected with D. immitis and 15 (1,3%) with D. reconditum. In the southern coastal area there was an estimated prevalence of 12.7% for D. immitis. D. immitis and D. reconditum microfilaria were 298.1 micrometer and 249.2 micrometer long and 7.3 micrometer and 4.4 micrometer wide, respectively. A Witness immunotest that detects D. immitis antigen was used to confirm parasitological results and reveal occult dirofilariasis cases. Of the total 6,579 females examined, 8 (0.1%) Culex quinquefasciatus were observed to be naturally infected with D. immitis larvae. These results proved dirofilariasis transmission in Maceió and demonstrated D. reconditum in the same geographic area.

Using antigen capture and filter tests, 6,078 dogs throughout the state of Washington were examined for filariasis between July 1, 1997 and October 31, 1999. In western Washington, 791 males and 901 females examined were outdoors, not on prophylaxis, and had traveled out of the state; 6/791 (0.8%) males and 7/901 (0.8%) females were infected with Dirofilaria immitis (D. immitis), and one (0.1%) male and one (0.1%) female were infected with Dipetalonema reconditum (D. reconditum). There were also 392 males and 362 females examined that were outdoors, not on prophylaxis, and had not traveled out of western Washington. One (0.1%) female was infected with D. immitis, and two (0.5%) males and one (0.2%) female were infected with D. reconditum. In eastern Washington, 707 males and 826 females examined were outdoors, not on prophylaxis, and had traveled out of the state; 9/707 (1.0%) males and 4/826 (0.5%) females were infected with D. immitis, and no D. reconditum was found. There were also 376 males and 412 females examined that were outdoors, not on prophylaxis, and had not traveled out of the state. Three (0.8%) males and three (0.7%) females had D. immitis. One (0.2%) female had D. reconditum. Distribution of D. immitis-infected, nontravel dogs in eastern Washington was only found between 120 degrees and 119 degrees west longitude in the communities of Richland, Moses Lake, Okanogan, and Omak. Enzootic transmission of D. immitis and D. reconditum is occurring in both eastern and western Washington.

The gene encoding the cytoplasmic copper/zinc superoxide dismutase (AVSOD1) from the filarial parasite Acanthocheilonema viteae was isolated from a genomic DNA library using a degenerate oligonucleotide probe. Additionally, cDNAs of the AVSOD1 and the secreted extracellular SOD (AVSOD2) were both cloned by RT-PCR, and the AVSOD2 was expressed at high levels in E. coli. The amino acid sequence of the AVSOD1 is 89.5 and 87.5% identical to that of the corresponding enzymes of Brugia pahangi and Onchocerca volvulus, respectively. In contrast, the AVSOD2 shows a lower degree of identity to the other filarial SODs and is extensively glycosylated. RT-PCR studies demonstrate the expression of both SOD subtypes in all developmental stages of A. viteae and indicate up-regulation of the AVSOD2 expression after transmission from the vector to the definitive host. This suggests an enhanced requirement for SOD activity in post-infective larval stages and adults of A. viteae. ELISAs performed with purified recombinant AVSOD2 show that the AVSOD2 is not a major target for the immune system in naturally infected jirds.

Field and laboratory studies were performed in order to assess the degree of canine dirofilariasis caused by Dirofilaria immitis (Leidy) in the Baix Llobregat region, a fluvial area near Barcelona, Spain. A total of 188 dogs were sampled between May and August of 1994. Three main areas were chosen: the Western Delta, the Eastern Delta and the Northern zone. Simultaneously, a mosquito sampling programme was carried out with CO2 light traps, to search for infective larvae (L3) of D. immitis. Of the 188 dogs sampled, 38 were positive for at least one of the three filaria found: D. immitis 12.8%, Dipetalonema reconditum (Grassi) 3.7% and Dipetalonema dracunculoides (Cobbold) 2.7%. Only 1.1% showed a mixed infection of both D. immitis and D. dracunculoides. Although Dirofilaria repens Raillet et Henry has been found in Spain, it was not found in this study. Comparing the three zones of the Baix Llobregat, the Eastern Delta showed the highest level of D. immitis (35.3%), probably due to the presence of Aedes caspius (Pallas). Despite the effort in sampling the mosquito population, D. immitis was not found in any of the 2001 females dissected, belonging to 5 species.

To assess the current status of Dirofilaria immitis infection and to determine whether there were other canine filarial infections in north Taiwan, postmortem examination was conducted in 180 stray dogs more than 12 months old. Blood and serum samples were examined using a modified Knott's test and an antigen-detecting enzyme-linked immunosorbent assay (ELISA) kit, respectively. Filarial infection was found in 60.6% of the dogs: 55% with D. immitis and 12.2% Dipetalonema reconditum. Moreover, the ELISA was determined to be more sensitive than the Knott's test. Although canine heartworm infection in Taiwan has been attributed to the unrestricted import of dogs from endemic areas, the results of this study indicate that transmission of D. immitis and Dip. reconditum may occur indigenously in the local canine population. This study is also the first record of Dip. reconditum in Taiwan.

Between June 1993 and May 1996 infections with filariae were diagnosed in 80 dogs. Five animals were infected with Dirofilaria repens and three other dogs with Dipetalonema reconditum. One of the D. reconditum positive dogs was also infected with Dirofilaria immitis. An epidemiological analysis of the cases was possible for three D. repens and two D. reconditum infected dogs. Two of the dogs with D. repens infections had been imported from Italy or Greece, the third dog had been taken by its owner to Hungary and former Yugoslavia. The dogs infected with D. reconditum were imported from Corse or Spain. Regarding the other 72 dogs with filariae, 45 animals were infected with D. immitis. For 27 dogs being negative in the D. immitis ELISA, microfilariae have been demonstrated. However, a histochemical species differentiation of the microfilariae was not possible because fresh blood smears were not available.

Three species of rodents were immunized with 50 irradiated (35 krad) stage-3 larvae (L3) of the filaria Acanthocheilonema viteae and challenged with an infection of normal L3. The immunization induced a significant reduction of the worm burden developing from the challenge infection in all host species, the jird (Meriones unguiculatus), the multimammate rat (Mastomys coucha) and the golden hamster (Mesocricetus auratus). The induced resistance was highest in jirds (92.5 +/- 9.7) followed by golden hamsters (59.4 +/- 26.6) and multimammate rats (55.1 +/- 40.4). The time course of antibody response against antigens of L3, adult worms and microfilariae, as studied by ELISA, showed quantitative and qualitative differences between the species. The antibody response against L3 antigens in immunoblots was similar in all species. Only one of the golden hamsters developed an antibody response against the surface of vector derived L3, while sera of jirds and multimammate rats did not react with L3 surface.

The prevalence of filariae in wild raccoons trapped in southeast Georgia was determined. Examination of blood samples revealed that 74 of 113 raccoons (66%) trapped in 6 southeastern Georgia counties were infected. Seventy-three of these raccoons (65%) were infected with Mansonella llewellyni and this parasite was observed in raccoons from every location examined. Dirofilaria tenuis was found in 22 raccoons (20%) and was observed in only 3 of the 6 counties surveyed. An adult specimen of Acanthocheilonema procyonis was found in the subcutaneous tissues of 1 of 5 necropsied raccoons. This is the first record of filariae in raccoons from Georgia. In addition, Dirofilaria-like larvae were found in Aedes taeniorhyncus mosquitoes collected in Liberty County.

A field survey aimed at updating knowledge of the distribution and prevalence of filarial infections in the Piedmont region was undertaken. Blood samples were collected from 2628 dogs (10-15 dogs/100 km2) which had remained in the local area, were kept in the open overnight, were more than 2 years old and had not previously been treated with microfilaricidal drugs. Infection was diagnosed by a modified Knott test. Comparison of the results with those from a similar survey carried out 25 years ago showed a 3-fold increase in the size of the endemic area, with the colonization of new habitats, and a 4-fold increase in the prevalence of Dirofilaria immitis infection.

Blood samples from 50 dogs with episodic weakness and 50 clinically normal dogs, all belonging to hunting breeds, were examined for microfilariae using the modified Knott's method. The prevalence of microfilaraemia in dogs belonging to the episodic weakness group was 10% for Dirofilaria immitis, 30% for Dirofilaria repens and 8% for Acanthocheilonema reconditum. In the clinically normal group, the figures were 14% for Dirofilaria repens and 4% for Acanthocheilonema reconditum. The overall percentage of dogs with microfilaremia in the episodic weakness group was 44 and that of the clinically normal group 16, with a statistically significant difference (P < 0.01). The prevalence of microfilaremia due to the nonpathogenic filarial species (Dirofilaria repens, Acanthocheilonema reconditum) was 34% and 16% for the episodic weakness group and the clinically normal dogs, respectively, with no significant difference.

After i.v. injection of 305 x 10(3) microfilariae (mf) per animal (50 g) into naive jirds, 50.8% of them could be recovered at autopsy 15 min later. Of these, 65.8% were calculated to be in the peripheral circulating blood (PCB) and were completely intact; 18.6% were recovered by perfusion of the lungs and 13.6% from the liver. In both organs about half the mf were associated with adherent lymphocytes and neutrophils but a few were partly disintegrated. Only 2.6% were recovered from the kidneys and the spleen. In long-term injection experiments using the same inoculum size the autopsy was done 15 min and 1, 3 and 6 weeks post-injection (p.i.) of mf into naive jirds. Throughout the experimental period the density of mf remained more or less constant in the PCB, but 3 weeks p.i. the density in the lungs increased up to 14 times to that in the PCB, whereas in the liver it decreased at the same time to a density similar to that in the PCB. In patent animals with adult worms delivering mf these were distributed as follows: 34.7% were calculated to be in the PCB; 24.4% were obtained by perfusion from the lungs and 22.0% from the liver; the rest were found in the kidneys (16.6%) and spleen (2.3%). In the lungs and the liver about 5/6 were associated with adherent cells, partly disintegrated or as fragments. In view of the fact that very few mf become disintegrated immediately after i.v. injection and also from their extremely long sojourn in the PCB, a low turnover rate of mf is presumed.(ABSTRACT TRUNCATED AT 250 WORDS)

Examinations were carried out in Białowieska Forest, Borecka Forest, Lower Silesian Forest, woods in Olsztyn District, Słowiński National Park, and in experimental hunting areas of the Forest Research Institute in Iława and of the Warsaw Agricultural University in Rogów. Samples of the skin from the ear and nose were taken from 136 shot roe deers. Skin samples were cut into 1-2 mm pieces, incubated in a physiological solution in 25 degrees C for 24 hours and examined for the presence of microfilariae. Microfilariae of Dipetalonema rugosicauda were found in roe deers in all examined hunting grounds. Prevalence of invasion oscillated from 6.6% to 57.1%. The wide dispersion of D. rugosicauda in Poland is caused by common occurrence in our country of the intermediate host and vector of this nematode--tick Ixodes ricinus.

A group of 358 owl and squirrel monkeys imported from Colombia, Peru, and Bolivia for the U.S. Agency for International Development Malaria Vaccine Development Program was examined for trypanosomes and microfilariae. Trypanosoma rangeli, isolated by hemoculture from Aotus nancymai, Saimiri b. boliviensis, and S. b. peruviensis, accounted for 76.6% of all trypanosome infections. Trypanosoma cruzi was isolated from 25 of 194 S. b. boliviensis, including two mixed infections with T. rangeli. Identifications of trypanosomes were confirmed by blinded tests with a panel of five rRNA probes on a subsample of cultures identified morphologically. Although no trypanosomes were isolated from Aotus vociferans or A. lemurinus griseimembra, positive serologic responses to T. cruzi were observed by indirect immunofluorescence assay in all species of monkeys examined and ranged from 42.1% among S. b. peruviensis to 92.3% among A. vociferans. Among T. rangeli-infected monkeys, 43.7% were seronegative for T. cruzi. No microfilariae were found in S. b. boliviensis or A. l. griseimembra. Mansonella barbascalensis and Dipetalonema caudispina were observed in A. vociferans, M. panamensis in A. nancymai, and M. saimiri and D. caudispina in S. b. peruviensis. Such naturally occurring infections in imported animal models are potential sources of accidental transmission to animal handlers and uninfected laboratory animals and can introduce confounding variables into otherwise well-planned and well-executed studies.

A dog naturally infected with Dipetalonema dracunculoides and having a microfilaremia of 6050 microfilariae per mm3 of blood was used as source of infection. Experimentally cultivated nymphs of Rhipicephalus sanguineus were fed on the donor dog. Once engorged, ninety-three nymphs were removed and kept at 30 degrees C and RH 90% until they moulted to the adult stage. To study the development of microfilariae in the vector, ten ticks were dissected at Day 37 post-infection. Adult infected ticks were fed on two uninfected dogs. The observed pre-patent periods were 69 and 76 days. Trans-stadial transmission of Dipetalonema dracunculoides by Rhipicephalus sanguineus was demonstrated.

Millardia meltada were infected with Acanthocheilonema viteae and examined for their susceptibility. The morbidity of infected M. meltada was low compared with that of jirds. On day 47 post-infection (p.i.), 13 of 14 M. meltada developed microfilaremia. Male M. meltada then showed gradually increasing microfilaremia with a peak level of 7000 per 30 microliters blood at week 20 p.i., which was much higher than that (3000) of male jirds. In contrast, microfilarial densities of female M. meltada were markedly low with a peak level of 200 during weeks 10-12 p.i. A simple centrifugation technique with Lympholyte-M was devised for microfilarial separation from the peripheral blood of infected M. meltada and yielded approximately 17 x 10(5) viable microfilariae from 1 ml of blood. This method also makes it possible to collect microfilariae from the same individuals repeatedly. M. meltada, coupled with this microfilarial separation technique, serves as a useful animal model for microfilarial studies of A. viteae.

During vaginal fluid examinations (Papanicolaou) to study the physiological sexual cycle of Cebus sp., abundant Dipetalonema gracile microfilariae (110-160 microns x 4-5 microns, without a sheath) were encountered in the genital fluid, but not in peripheral blood. Considering the great difficulty in diagnosing this obscure parasitosis, exfoliative colpocytology was found to be an efficient diagnostic.

Clinical records of 6,977 dogs examined at the small animal clinic of the University of Tennessee College of Veterinary Medicine from January 1980 through December 1989 were analyzed to determine the prevalence and changing frequency of Dirofilaria immitis and Dipetalonema reconditum infection. Using the Knott's test on these dogs, 805 (11.54%) tested positive for microfilariae, with D immitis in 430 dogs (6.16%), and Dip reconditum in 375 dogs (5.37%). Statistical analysis confirmed that the prevalence of D immitis and that of Dip reconditum were essentially equal in the population of dogs included in this study. There was a slight decrease in the prevalence of D immitis over the 10 years examined, but the prevalence of Dip reconditum remained constant. The results were not affected by year-to-year variability in the number of examinations performed. On the basis of our findings, in eastern Tennessee, those veterinarians who diagnose heartworm infection by the presence of microfilariae without differentiating the species involved, risk misdiagnosing 50% of the cases. If the patterns of prevalence seen in recent years continue, the chances of error may actually increase.

Susceptibility of Apodemus sylvaticus and A. agrarius to infection with Acanthocheilonema viteae was compared with that of hamsters and jirds. Microfilaremia in A. sylvaticus was first noted on day 52 post-infection (p.i.) and lasted during the course of the study (up to day 150 p.i.). Maximum microfilaremic levels (female worm basis) of A. sylvaticus [mean +/- S.D. (n) = 690 +/- 1288(6)] were considerably higher than those of hamsters [16 +/- 18(6)] and jirds [51 +/- 25(5)]. Adult worm recovery in A. sylvaticus ranged from 2 to 40% of the number of infective larvae inoculated. Worm development in A. sylvaticus resembled that in hamsters and jirds. In contrast, microfilaremia was not detected in, nor adult worms recovered from A. agrarius throughout the study.

A survey for filarial parasites was carried out on dogs in Lebanon. The peripheral blood was examined for microfilariae and the skins and carcasses for adult worms. Three methods were used for blood examination: (a) thick blood films stained with Giemsa; (b) a modified Knott's technique (Methylene Blue stained); (c) sodium citrate technique. Two species of filarial worm were found, Dipetalonema reconditum and another species of Dipetalonema which will be described in a later paper. The morphology of microfilariae and adults of D. reconditum is described. The microfilariae of D. reconditum showed a nocturnal sub-periodicity. Attempts were made to find vectors by feeding Aedes aegypti, Aedes phoeniciae, Culex pipiens molestus and Clenocephalides felis on an infected dog. Developing and infective stages were recovered only from C. felis.

Random-source dogs (n = 100) in Virginia and North Carolina were surveyed for the microfilariae of Dirofilaria immitis. Microscopic examination of fresh thin-films and modified Knott preparations were made. Dirofilaria immitis and Dipetalonema reconditum were found in 19% and 6% of the animals, respectively. There was no animal that harbored both species. Prevalence was significantly higher in North Carolina (28.6%) than in Virginia (13.6%) (P less than 0.025). Mean PCV was significantly lower (P less than 0.005) in infected vs noninfected animals.

Dipetalonema dessetae in Proechimys oris is a new model of rodent feafilariasis with several interesting features with respect to its utilisation in antifilarial pharmacology. 1. In the first part of these studies, it has been shown that the final host of the filaria, a rodent, was easy to breed. A prolific mosquito Aedes aegypti was an effective vector, and with the selected mode of infection i.e. 200 infesting larvae subcutaneously injected, 80% of the rodents were infected. 2. From 90 to 150 days p.i., the microfilaria count increased and reach a plateau which was maintained during 60 days. This plateau has enabled the evaluation of microfilaricidal activity. A drug exhibited a significative (0,10) microfilaricidal activity in two animals if the microfilaremia were reduced to 87% and 83,6% of pretreatment values, two or six weeks after treatment. 3. Identically, a compound would present a significative (0,12) macrofilaricidal effect if not a single male and not more than 1,6 female filaria were found at the autopsy of both animals six weeks after treatment. Activity on immature worms (3rd and 4th instar larvae, young adults) was qualitatively evaluated by the presence or absence of filaria at the autopsy of rodents which have been treated at various dates depending of the stages. 4. The sensitivity of this model was evaluated with several known antifilarial drugs, some of them unused by human patients. Diethylcarbamazine, levamisole, suramin, mebendazole and flubendazole killed adults, microfilariae and infesting larvae. Mel W was mainly macrofilaricidal and trichlorfon active on mf. Among all laboratory filariae, D. dessetae in P. oris is one of the most sensitive rodent models and, as such, would serve for the primary screening of new chemical compounds and for the pharmacological studies of antifilarial drugs.

The prevalence of Dirofilaria immitis and Dipetalonema reconditum infections in Missouri dogs was investigated by means of a statewide veterinary mail survey and a study of shelter dogs from central Missouri and Mississippi River communities. The veterinary survey revealed microfilariae of D immitis in 447 of 11,823 (3.8%) dogs, microfilariae of D reconditum in 14 (0.1%), and microfilariae of both species in 8 (less than 0.1%). Of 493 shelter dogs examined, using the modified Knott test, 23 (4.7%) were positive for D immitis, 23 (4.7%) for D reconditum, and 2 (0.4%) for both helminths. The prevalence of infection with both D immitis (9.4%) and D reconditum (6.3%) was higher in shelter dogs from the Mississippi River communities than in those from central Missouri (1.7% for D immitis, 3.7% for D reconditum). The microfilariae of D immitis in shelter dogs ranged in length from 255 to 343 micrometer (mean, 314 micrometer) and in width from 5.0 to 7.5 micrometer (mean, 6.5 micrometer); those of D reconditum ranged in length from 238 to 295 micrometer (mean, 257 micrometer) and in width from 3.2 to 6.5 micrometer (mean, 4.9 micrometer). Buttonhook tails were seen in 41% of D reconditum. In the final analysis, the shape of the anterior end was considered the most reliable criterion for differentiation.

Blood samples from 331 greyhounds in the Hunter Valley and nearby coastal areas of New South Wales were examined for microfilariae using a filtration technique. Species were identified by histochemical staining; 10.9% of the greyhounds were infected with Dirofilaria immitis and 3.6% with Dipetalonema reconditum. The prevalence of infection of both species was significantly greater in summer than in winter (p = less than 0.05). Infection with D. immitis was correlated with differences in age, sex, bodyweight and coat colour, and a reported lack of stamina and the presence of a cough. No significant association was found. Diethylcarbamazine citrate was used for prophylaxis in 8.8% of all the greyhounds examined.

Six male and 6 female Beagles, 6 to 7 months old, were allotted to 2 groups: group I--inoculated subcutaneously with 30 Dipetalonema reconditum infective larvae/dog, and group II--noninoculated controls. Group comparisons were made in regard to hematologic values, Knott test results, body weights, blood urea nitrogen, total serum protein, serum albumin and alanine aminotransferase and creatine kinase activities. Routine urinalysis data were compared at 1 week before and at 28 weeks after the inoculations. Mean total leukocyte counts were significantly (P less than 0.05) greater in group I dogs than in group II dogs at postinoculation weeks (PIW) 4, 5, and 7 to 12, and mean eosinophil counts were significantly greater in group I dogs at PIW 3 to 11, 13 to 15, 20, and 23 to 24. Microfilariae were detected as early as the 10th week and sporadically thereafter. Only 1 D reconditum adult worm was recovered from all of the inoculated dogs. Five other dogs (group III) with chronic, patient experimentally induced dipetalonemiasis, were evaluated with the same tests at PIW 70 to 89. Eosinophilia (greater than 750 cells/microliter) was present in 4 of 5 dogs; lymphocytosis (greater than 4,800 cells/microliter) was evident in 1 dog. Proteinuria (greater than or equal to 30 mg/dl) was detected in 3 of 4 dogs with chronic dipetalonemiasis.

Description of D. freitasi n. sp., a parasite of Cebus capucinus: this species, close to D. caudispina, is distinguished by the slightly more complex structure of the vagina and right spicule, the lack of area rugosa on the tail and by the shorter microfilaria. Additional morphological data on the male of D. robini Petit et al., 1985 are given. A comparative table of 4 principal evolutive characters of the genus Dipetalonema (vagina, left and right spicules, epithelio-muscular body wall) is given. D. caudispina and D. freitasi n. sp. represent a small primitive group opposed to the more evolved one made up of D. robini, D. gracile and D. graciliformis.

Endoparasites detected in the black-bellied whistling duck (Dendrocygnaautumnalis) include one nasal mite, four nematodes, three trematodes, five cestodes, and two acanthocephalans. Each of these represents a new host record. Overall, 47% of the birds were parasitized with an average of 12 helminths per infected bird. Helminths were significantly more common in juveniles than in adults; more females than males were parasitized, but the difference was not statistically significant. No correlation existed between the parasite load and the physical condition of the host. Tissue damage in infected birds was minimal and limited to nematode cysts in the proventriculi. Parasite loads were light, apparently reflecting the food habits of the host.