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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.

Background Dirofilaria immitis is responsible for heartworm disease in dogs in endemic areas worldwide. Screening for this infection is done by blood tests. Antigen testing is the most sensitive method to detect an infection with adult (female) worms. Microscopic examination of a blood smear or Knott’s test can be used to detect circulating microfilariae, the infective larvae. To increase the sensitivity of the antigen test by decreasing the false negative test results, heating of the blood sample has been recommended in recent guidelines. Heating is believed to remove blocking immune-complexes. Circulating microfilariae are not specific findings for heartworm infection, as other nematodes (among others, Acanthocheilonema dracunculoides) can also result in microfilaremia. Although the type of microfilariae cannot be determined by microscopy alone, real-time PCR can reliably identify the infecting nematode species. Correct identification of the parasite is of major importance, as an infection with D. immitis requires antiparasitic therapy, whereas A. dracunculoides is thought to be a clinically irrelevant coincidental finding. The present case report describes a microfilaremic dog where the initial antigen test for D. immitis turned positive after heat treatment, whereas real-time PCR revealed that the microfilariae were A. dracunculoides (syn. Dipetalonema dracunculoides). Results A circa 5-year old, asymptomatic Spanish mastiff dog was referred for heartworm therapy because microfilariae were found via a screening blood test. The dog was recently imported to the Netherlands from Spain, where it had been a stray dog. Antigen tests on a plasma sample for D. immitis were performed with three different test kits, which all turned out to be negative. However, heat treatment of two of these samples were carried out and both of them led to a positive antigen test result. Real-time PCR showed that the circulating microfilariae belonged to A. dracunculoides species. Three administrations of moxidectin spot-on at monthly intervals resulted in a negative antigen and a negative Knott’s tests one month after the last treatment. Conclusions We conclude that heat treatment of initially negative blood samples for D. immitis could lead to false positive antigen test results if the dog is infected with A. dracunculoides.

The current study is the first attempt to include the many records from wild primate host species from the Helminthological Collection of the Oswaldo Cruz Institute (CHIOC), Rio de Janeiro, Brazil, along with updated information based on literature. We list a total of 50 species of helminth parasites associated with 46 species of wild primates in Brazil. A total of 814 records of helminths in wild primates from Brazil were listed, including 406 samples of helminths stored in the CHIOC. Of these samples, 16 are new host records (NHR). The majority of these helminth species are nematodes with 30 species reported, which corresponds to 60% of the total number of helminths. The helminth species with more host species is the nematode Dipetalonema gracilis (Filarioidea, Onchocercidae), associated to 13 species of primates. The primate species with more reports of helminths in Brazil is Saimiri sciureus (Cebidae), with 16 species (13 nematodes, 3 acanthocephalans). In the current study, 46 species of primates have at least 1 species of helminth recorded, which represents approximately 39% of species of this host in Brazil. Therefore, we can conclude that the helminths documented in wild primates from Brazil are obviously underestimated, since the helminth fauna in the majority of Brazilian primates remains unknown.

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.

Aim The present investigation was conducted to study the prevalence of microfilaremia in dogs in Gujarat. Materials and methods A total of 418 adult dogs aged between 2 and 14 years with signs of weakness and non-specified complaints, presented at TVCC, Deesa (North Gujarat), Nandini Veterinary Hospital, Surat (South Gujarat), and Private Clinics, Ahmedabad (Central Gujarat), were included in the present investigation for studying the prevalence of microfilaremia from July 2016 to May 2017. Results A total of 418 dogs were screened, of which 33 were found positive for circulating microfilariae with the prevalence rate of 7.89% in the population. Among microfilaremic dogs, the finding of microfilariae of Dipetalonema (Acanthocheilonema) reconditum was more common (23 cases; 69.69%) than Dirofilaria immitis (10 cases; 30.30%) making their prevalence in the population of 418 dogs as 5.50% and 2.39%, respectively. Breed-wise distribution of microfilaremic dogs revealed that 12 (36.36%), 8 (24.24%), 5 (15.15%), 4 (12.12%), 2 (6.06%), 1 (3.03%), and 1 (3.03%) cases were observed in Pomeranian, non-descript, German Shepherd, Labrador, Great Dane, Lhasa Apso, and Pug dogs, respectively. Of 10 cases of D. immitis, 5, 2, 2, and 1 were observed in Pomeranian, Labrador, non-descript, and Great Dane dogs, respectively. Cases of Dipetalonema reconditum were highest in Pomeranian (7), followed by non-descript (6), German Shepherd (5), Labrador (2), Great Dane (1), Lhasa Apso (1), and Pug (1). Age-wise distribution recorded significantly (p≤0.01) higher number of cases in adult dogs (4-14 years) for D. immitis (30.30%) and D. reconditum (39.39%). Sex-wise distribution of microfilaremic dogs showed that male (22/33, 66.66%) was more predisposed to microfilaremia rather than females (11/33, 33.34%). It is apparent from the study that the number of dogs with microfilaremia due to D. reconditum was significantly (p≤0.01) higher than that of D. immitis. Conclusion The present study revealed that microfilaremia due to D. immitis and D. reconditum is prevalent in the state of Gujarat. The infection with D. immitis was associated with severe lung and cardiac pathological manifestations.

Dipetalonema gracile (Rudolphi, 1809) (Filarioidea: Onchocercidae) is one of six species of cavities filarial parasites of Neotropical non-human primates. The present study recorded the occurrence of D. gracile, provides morphological and morphometric data and extends the geographical distribution. Adult filariae were obtained from the thoracic and abdominal cavities of 38 specimens of woolly monkey, which were used for local human consumption, in the northeastern Peruvian Amazon. Male and female filarids were processed and analysed using light and scanning electron microscopy. Details of the cephalic papillae, post-cloacal bands and papillae, vulva, phasmid position and lateral appendages are showed by scanning electron microscopy and is recorded the occurrencce of Lagothrix poeppigii monkey as a new host of this filaria in the Yavari-Mirin river basin, Peruvian Amazon. Resumo Dipetalonema gracile (Rudolphi, 1809) (Filarioidea: Onchocercidae), é uma das seis espécies de filarias parasitas de primatas não humanos neotropicais. O presente trabalho registra a ocorrência de D. gracile , proporciona dados morfológicos e morfométricos e amplia sua distribuição geográfica. Filárias adultas foram obtidas da cavidade torácica e abdominal de 38 espécimes de macaco barrigudo, que foram utilizados para consumo humano local. Essa espécie de primatas não humanos neotropicais tem distribuição ao nordeste da Amazônia peruana. Filarídeos machos e fêmeas foram processados e analisados pela microscopia de luz e microscopia eletrônica de varredura. Detalhes das papilas cefálicas, bandas e papilas pós-cloacais, vulva, posição dos fasmídeos e apêndices laterais são mostradas pela microscopia eletrônica de varredura e registra-se a ocorrência do macaco Lagothrix poeppigii como novo hospedeiro desta filaria na bacia do rio Yavari-Mirin na Amazônia peruana.

Following chronic retinol (vitamin A) deprivation leading to exhaustion of liver vitamin A reserves below 50 I.U. per liver hamsters were fed diets either deficient in (“Rd”: 250 I.U.A/kg in experiment I, 1000 I.U.A/kg in experiment II) or enriched with retinol (“Rw”: 10000 I.U.A/kg in experiment I and II). After 4 weeks some of the animals (36 in experiment I, 30 in II) were infected with 150 3rd-stage larvae of D. viteae, while clean animals were kept as controls. The retinol status, the immune response (indirect fluorescent antibody test: IFAT) and parasitological parameters were examined up to 8 (experiment I) and 12 weeks (experiment II) post infection (p.i.). Rd hamsters had levelling off of weight gain or weight loss, severely deficient retinol levels in serum and liver, and high mortality. Weight gain was less in infected than in uninfected hamsters, and the capacity of infected Rw animals to restore liver retinol was significantly lower than that of uninfected Rw animals. IFAT titres were similar in Rd and in Rw animals, but microfilaraemia was significantly enhanced at 8 and 10·5 weeks p.i. in Rd hamsters. While the number of worms recovered from Rd and Rw hamsters was similar, there was a significant increase in the ratio of female to male worms in Rd hamsters. Rd hamsters in experiment I produced 3·3 times the worm mass per 100 g body-weight than Rw hamsters. Also, the average mass per female worm was significantly higher in Rd than in Rw hamsters, and this parameter was negatively correlated with the liver retinol concentration in experiment I (r=−0·89). Retinol deficiency has a marked effect on growth and fertility of D. viteae in hamsters.

Parasite-host relationships are influenced by several factors intrinsic to hosts, such as social standing, group membership, sex, and age. However, in wild populations, temporal variation in parasite distributions and concomitant infections can alter these patterns. We used microscropy and molecular methods to screen for naturally occurring haemoparasitic infections in two Neotropical primate host populations, the saddleback (Leontocebus weddelli) and emperor (Saguinus imperator) tamarin, in the lowland tropical rainforests of southeastern Peru. Repeat sampling was conducted from known individuals over a three-year period to test for parasite-host and parasite-parasite associations. Three parasites were detected in L. weddelli including Trypanosoma minasense, Mansonella mariae, and Dipetalonema spp., while S. imperator only hosted the latter two. Temporal variation in prevalence was observed in T. minasense and Dipetalonema spp., confirming the necessity of a multi-year study to evaluate parasite-host relationships in this system. Although callitrichids display a distinct reproductive dominance hierarchy, characterized by single breeding females that typically mate polyandrously and can suppress the reproduction of subdominant females, logistic models did not identify sex or breeding status as determining factors in the presence of these parasites. However, age class had a positive effect on infection with M. mariae and T. minasense, and adults demonstrated higher parasite species richness than juveniles or sub-adults across both species. Body weight had a positive effect on the presence of Dipetalonema spp. The inclusion of co-infection variables in statistical models of parasite presence/absence data improved model fit for two of three parasites. This study verifies the importance and need for broad spectrum and long-term screening of parasite assemblages of natural host populations., Graphical abstract Image 1, Highlights • Co-infection data improves statistical models of parasite prevalence. • Longitudinal sampling is key to unraveling parasite-host relationships in nature. • Host specificity of blood parasites among sympatric Callitrichine primates. • Sex roles in cooperatively breeding primates may not impact parasitism.

ES-62 is an immunomodulatory phosphorylcholine (PC)-containing glycoprotein secreted by the rodent filarial nematode Acanthocheilonema viteae. Previously, the use of knockout mice has revealed the effects of ES-62 on macrophages and dendritic cells to be dependent on TLR4. However, it is possible that ES-62 may interact with additional proteins on the surfaces of target cells and hence that cells may vary with respect to receptor usage. In this study, we identified by molecular weight, proteins that interact with ES-62 and found differences amongst the immune system cells studied. Thus, whereas lymphocytes appear to have two major interacting proteins of ∼135 and ∼82 kDa, U937 monocytes only contain an ES-62-binding protein of the latter molecular weight. Binding to the proteins on B cells and U937 cells was blocked by PC, suggesting a critical role for this ES-62 moiety in facilitating interaction. Finally, ES-62 binding is followed by internalization in both macrophages and B cells but only in the former was absence of TLR4 found to block internalization. These findings are consistent with differences in receptor usage by ES-62 amongst different cell-types.

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.

Chitinases of pathogens have been proposed as potential targets of vaccines or specific inhibitors. We studied the genomic organization, transcript levels, developmental expression, and biological function of chitinases in the rodent filarial nematode Acanthocheilonema viteae , a model organism for human-pathogenic filarial worms. Characterization of nine genomic clones from an A. viteae phage library and Southern blot experiments revealed the existence of three different chitinase genes, two of which could theoretically yield functional transcripts. The deduced proteins of these genes had the common modular organization of family 18 chitinases. Northern blot experiments and rapid amplification of cDNA ends-PCR with adult worms and larval stages showed that only one gene is expressed, with high variation in transcript levels, as determined by real-time PCR. Chitinase transcript levels were lowest in the late male stage 4 larva (L4) and peaked in the stage 3 larva (L3), which was corroborated by Western blotting. RNA interference (RNAi) experiments showed that treatment of L3 and adult female worms with double-stranded RNA of chitinase inhibited molting of L3 worms and hatching of microfilariae. RNAi also led to the death of 50% of female worms, revealing the essential role of chitinase in the life cycle of filarial nematodes.

In an attempt to study the occurrence of concomitant immunity in filarial infections, jirds (Meriones unguiculatus) were experimentally infected with Acanthocheilonema viteae, and patent animals were superinfected with a defined dose of A. viteae stage 3 larvae (L3). Infected animals harbored significantly less worms deriving from the superinfection than the control group (P < 0.05, 56.2%, and 63.4% protection), as shown by analysis of female worms 6 wk after superinfection on the basis of their developmental status and their length. This protection was not due to contact with L3 antigens because a significant reduction of worm burdens deriving of a superinfection was also observed after subcutaneous implantation of a single female worm (P < 0.05, 40.2% and 64.9% protection). The induced protective responses target L3 and restrict their migration because an established infection resulted in a reduction of L3 recovery (95.6% and 94.3%, P < 0.001) from tissues of jirds at day 5 after superinfection. Other data show that L3 from a superinfection are trapped within eosinophil-rich granulomas, which is likely to create unfavorable conditions for the worms and to lead to later death. Taken together, established A. viteae-infections partially protect hosts against homologous superinfection by an immune-mediated mechanism and, thus, regulate the population density of the parasites within the host by concomitant immunity.

Ov20 is a structurally novel 20-kDa retinol binding protein secreted by Onchocerca volvulus . Immunological and biological investigation of this protein has been hampered by the inability to maintain O. volvulus in a laboratory setting. In an effort to find a system more amenable to laboratory investigation, we have cloned, sequenced, and expressed cDNA encoding homologues of Ov20 from two closely related filarial species, Brugia malayi (Bm20) and Acanthocheilonema viteae (Av20). Sequence comparisons have highlighted differences in glycosylation of the homologues. We present here an analysis of mouse immune responses to Ov20, Bm20, and Av20. The results suggest a strong genetic restriction in response to native Bm20 that is overcome when recombinant, nonnative material is used. Reactivity of human filarial sera to the three recombinant proteins confirmed previous specificity studies with Ov20 but highlighted important differences in the reactivity patterns of the O. volvulus and B. malayi homologues that may be due to differences in glycosylation patterns. Ov20 is a dominant antigen in infected individuals, while Bm20 is not. The availability of the B. malayi homologue enabled us to use defined murine reagents and inbred strains for genetic analysis of responsiveness in a way that is not possible for Ov20. However, the close sequence similarity between Ov20 and Av20 suggests that the A. viteae model may be more suited to the investigation of the biological functions of Ov20.

Summary objective To determine mitogenic and antigen-specific cellular immune responses of two species of rodents, viz. Merionesunguiculatus and Mastomyscoucha to assess the usefulness of the A. viteae/Mastomys model for cellular immune studies in experimental filariasis. methods Lymphocyte blast transformation test (LTT) using spleen cells of normal and A. viteae infected animals. results The proliferative response of gerbils was much higher than that of Mastomys to both ConA and filarial antigens. Cells of both species of rodents did not respond to microfilarial (mf) antigen, however, their mitogenic response differed during infection. Some degree of nonspecific suppression was observed in gerbils during prepatent and patent stages of infection, while Mastomys revealed highest proliferation during patent microfilaraemia. Mastomys cells did not respond to adult or mf antigen,while adult-specific proliferation was detected in the case of gerbils. conclusion The A. viteae/gerbil model shows more similarity to human filarial infection regarding cellular immune response. Markedly low responsiveness of a high percentage of Mastomys and wide variations in the cellular response to nonspecific mitogen limit the usefulness of Mastomyscoucha in immunological studies, especially cellular immunity.

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.

Background Considering the increasing importance of small animals travel medicine and the spread of filariae with zoonotic potential to non-endemic European areas, routine filarial diagnosis in dogs is becoming important. Dirofilaria immitis, D. repens, Acanthocheilonema dracunculoides and A. reconditum are the most common canine filarial nematodes presenting blood circulating microfilariae (mf) which can be differentiated to species level by the acid phosphatase activity patterns or by PCR. Available data on the size of the mf vary considerably in the literature. The aim of this study was to validate morphometric criteria for filarial identification in blood samples of dogs after concentration of mf with the modified Knott’s technique. Methods Morphometric analysis of 10 mf from samples identified to species level by acid phosphatase activity and partially confirmed by PCR were performed with specimens from 377 dogs. Results The mean length and width of D. immitis mf from 60 dogs were 301.77±6.29 μm and 6.30±0.26 μm, of D. repens mf from 171 dogs 369.44±10.76 μm 8.87±0.58 μm, of A. dracunculoides mf from 133 dogs 259.43±6.69 μm and 5.09±0.47 μm and of A. reconditum mf from 13 dogs 264.83±5.47 μm and 4.63±0.52 μm. For a subset of 30 samples, morphometric analysis was repeated with identical results in two laboratories. Furthermore, the size of mf concentrated and fixed by the Knott’s technique was shown to be stable over 105 days. Conclusions The Knott’s test enables to clearly distinguish between D. immitis, D. repens and Acanthocheilonema spp. However, due to the overlapping size ranges of A. dracunculoides and A. reconditum, biochemical or molecular methods are required to distinguish these two species.

Acanthocheilonema viteae is a parasitic nematode of rodents. We identified the chitinase of A. viteae infective stage larvae (L3) as the main target of the humoral immune response of jirds, which were protected against challenge infection after vaccination with irradiation attenuated L3. The cDNA of the L3 chitinase has been sequenced, and the deduced amino acid sequence shows significant homologies to chitinases of Brugia malayi microfilariae, insects, yeast, bacteria, and Streptomyces sp. The protein has been characterized by monoclonal antibodies and substrate activity gels. The chitinase of L3 may contribute to degrading the nematode cuticle during molting and thus represents a target of protective immune responses in a phase where the parasite is highly vulnerable. In addition, it has been shown that a similar enzyme exists in uterine microfilariae, which probably has a role in casting the egg shell.

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.

Dipetalonema sp. Alouatta fusca (Geoffroy Saint-Hilaire), abdominal cavity, Espírito Santo (Vicente et al. 1992; Vicente et al. 1997) (CHIOC 29524)., Published as part of Muniz-Pereira, Luís C., Vieira, Fabiano M. & Luque, José L., 2009, Checklist of helminth parasites of threatened vertebrate species from Brazil, pp. 1-45 in Zootaxa 2123 on page 8, DOI: 10.5281/zenodo.188170, {"references":["Vicente, J. J., Pinto, R. M. & Faria, Z. (1992) Spirura delicata sp. n. (Spiruridae, Spirurinae) from Leontocebus mystax (Callithrichidae) and a check list of other nematodes of some brazilian primates. Memorias do Instituto Oswaldo Cruz, 87, 305 - 308.","Vicente, J. J., Rodrigues, H. O., Gomes, D. C. & Pinto, R. M. (1997) Nematoides do Brasil. Parte V: Nematoides de mamiferos. Revista Brasileira de Zoologia, 14, 1 - 452."]}

Dipetalonema caudispina (Molin) Ateles paniscus (Linnaeus), abdominal cavity, Pará (Freitas 1964) (CHIOC 9027, 15438 a̅k). Brachyteles arachnoides (Geoffroy), unspecified site of infection, Rio de Janeiro (Freitas 1943; Notarnicola et al. 2008). Leontopithecus rosalia (Linnaeus), unspecified site of infection, Pará (Freitas 1943; Notarnicola et al. 2008)., Published as part of Muniz-Pereira, Luís C., Vieira, Fabiano M. & Luque, José L., 2009, Checklist of helminth parasites of threatened vertebrate species from Brazil, pp. 1-45 in Zootaxa 2123 on page 8, DOI: 10.5281/zenodo.188170, {"references":["Freitas, J. F. T. (1964) Achegas Helmintologicas. Revista de Ciencias Biologicas, 2, 3 - 40.","Freitas, J. F. T. (1943) Estudios sobre nematodeos filarideos Dipetalonema caudispina (Molin, 1858). Memorias do Instituto Oswaldo Cruz, 38, 361 - 372.","Notarnicola, J., Pinto, C. M. & Navone, G. T. (2008) Host Occurrence and Geographical Distribution of Dipetalonema spp. (Nematoda: Onchocercidae) in Neotropical Monkeys and the First Record of Dipetalonema gracile in Ecuador. Comparative Parasitology, 75, 61 - 68."]}

Dipetalonema gracilis (Rudolphi) Ateles paniscus (Linnaeus), abdominal cavity, unspecified locality (Freitas 1964). Brachyteles arachnoides (Geoffroy), abdominal cavity, unspecified locality (Diesing 1851). Lagothrix lagotricha (Humboldt), abdominal cavity, unspecified locality (Freitas 1964; Vicente et al. 1997). Leontopithecus chrysopygus (Mikan), abdominal cavity, unspecified locality (Diesing 1851). Leontopithecus rosalia (Linnaeus), abdominal cavity, unspecified locality (Diesing 1851). Saguinus bicolor (Spix), abdominal cavity, unspecified locality (Diesing 1851)., Published as part of Muniz-Pereira, Luís C., Vieira, Fabiano M. & Luque, José L., 2009, Checklist of helminth parasites of threatened vertebrate species from Brazil, pp. 1-45 in Zootaxa 2123 on page 8, DOI: 10.5281/zenodo.188170, {"references":["Freitas, J. F. T. (1964) Achegas Helmintologicas. Revista de Ciencias Biologicas, 2, 3 - 40.","Diesing, K. M. (1851) Systema Helminthum, Vo l. I I. Wilhelmum Braumuller Vindobonae. 588 pp.","Vicente, J. J., Rodrigues, H. O., Gomes, D. C. & Pinto, R. M. (1997) Nematoides do Brasil. Parte V: Nematoides de mamiferos. Revista Brasileira de Zoologia, 14, 1 - 452."]}

Parasitic nematodes can downregulate the immune response of their hosts through the induction of immunoregulatory cytokines such as interleukin-10 (IL-10). To define the underlying mechanisms, we measured in vitro the production of IL-10 in macrophages in response to cystatin from Acanthocheilonema viteae, an immunomodulatory protein of filarial nematodes, and developed mathematical models of IL-10 regulation. IL-10 expression requires stimulation of the mitogen-activated protein kinases extracellular signal-regulated kinase (ERK) and p38, and we propose that a negative feedback mechanism, acting at the signalling level, is responsible for transient IL-10 production that can be followed by a sustained plateau. Specifically, a model with negative feedback on the ERK pathway via secreted IL-10 accounts for the experimental data. Accordingly, the model predicts sustained phospho-p38 dynamics, whereas ERK activation changes from transient to sustained when the concentration of immunomodulatory protein of Acanthocheilonema viteae increases. We show that IL-10 can regulate its own production in an autocrine fashion, and that ERK and p38 control IL-10 amplitude, duration and steady state. We also show that p38 affects ERK via secreted IL-10 (autocrine crosstalk). These findings demonstrate how convergent signalling pathways may differentially control kinetic properties of the IL-10 signal.

The possible involvement of transglutaminase-catalyzed reactions in survival of adult worms, microfilariae (mf), and infective larvae of the filarial parasite Brugia malayi was studied in vitro by using the specific pseudosubstrate monodansylcadaverine (MDC) and the active-site inhibitors cystamine or iodoacetamide. These inhibitors significantly inhibited parasite mobility in a dose-dependent manner. This inhibition was associated with irreversible biochemical lesions followed by filarial death. A structurally related, inactive analog of MDC, dimethyldansylcadaverine, did not affect the mobility or survival of the parasites. Adult worms failed to release mf when they were incubated in the presence of MDC or cystamine, and this inhibitory effect on mf release was concentration dependent. Similar embryostatic and macrofilaricidal effects of MDC were observed in Acanthocheilonema viteae adult worms. These studies suggest that transglutaminase-catalyzed reactions may play an important role in the growth, development, and survival of filarial parasites.

Biological samples were collected from dogs in resource-limited communities in the North-West and Gauteng Provinces of South Africa to assess the prevalence of helminth parasitism. These samples included adhesive tape peri-anal skin swabs and fresh faecal samples for helminth examination, and thick and thin blood films (smears) and whole-blood samples in anticoagulant for examination of filarial nematode microfilariae and haemoprotozoa. The eggs of Ancylostoma caninum, Toxocara canis, Toxascaris leonina, Dipylidium caninum and taeniids were identified. None of the blood samples and smears tested positive for microfilariae of Dirofilaria immitis or Dipetalonema spp. or for haemoprotozoa. The adhesive tape swabs were negative for cestode eggs and segments. Most of the helminth parasites identified in this study are zoonotic and consequently are regarded as a public health hazard.

Summary: The molecular analysis of the Filarioidea and the endobacteria Wolbachia is no more limited to the agents of human diseases and the diversified sampling permits a synthesis with the morphological and biological results. The validity of the genera with “uncoherent host range”, such as Mansonella, Litomosoides and Cercopithifilaria, is confirmed and, consequently, their evolution by host-switchings. Dirofilaria and Onchocerca, types of two subfamilies, appear more closely related than with other onchocercids. Waltonellinae from anurans and Oswaldofilariinae from reptiles have a basal position. These filariae, and some others also considered primitive, do not harbour Wolbachia. Evidence for transversal transmission of the bacteria and a second acquisition event is given with the supergroup F, identified in Mansonella, in one of the Cercopithifilaria species and in arthropods.

The coincidence between infections with parasitic worms and the reduced prevalence of allergic disease in humans and in animal models has prompted the search for helminth molecules with antiallergic and antiinflammatory potential. We report herein that filarial cystatin, a secreted protease inhibitor of filarial nematodes, suppresses Th2-related inflammation and the ensuing asthmatic disease in a murine model of OVA-induced allergic airway responsiveness. Treatment with recombinant filarial cystatin inhibited eosinophil recruitment, reduced levels of OVA-specific and total IgE, down-regulated IL-4 production, and suppressed allergic airway hyperreactivity when applied during or after sensitization and before challenge with the allergen. Depletion of macrophages by clodronate-containing liposomes prevented the curative effects and restored the levels of infiltrating cells, IgE, and allergic airway reactivity. Blocking of IL-10 by application of anti-IL-10 receptor Abs restored the reduced number of infiltrating cells and the levels of OVA-specific IgE. In contrast, depletion of regulatory T cells by anti-CD25 Abs had only limited effects. Cystatin also modulated macrophage-mediated inflammation in a murine model of dextran sulfate sodium-induced colitis, leading to reduction of inflammatory infiltrations and epithelial damage. Our data demonstrate that treatment with a single helminth protein can exert the antiallergic effects of helminth infections.

Neotropical primates of the Cebidae and Callitrichidae, in their natural habitats, are frequently infected with a variety of trypanosomes including Trypanosoma cruzi, which causes a serious zoonosis, Chagas' disease. The state of trypanosome infection after a 30-day quarantine period was assessed in 85 squirrel monkeys (Saimiri sciureus) and 15 red-handed tamarins (Saguinus midas), that were wild-caught and exported to Japan as companion animals or laboratory animals, for biomedical research, respectively. In addition to many microfilariae of Mansonella (Tetrapetalonema) mariae at a prevalence of 25.9%, and Dipetalonema caudispina at a prevalence of 3.5%, a few trypomastigotes of Trypanosoma (Megatrypanum) minasense were detected in Giemsa-stained thin films of blood from 20 squirrel monkeys at a prevalence of 23.5%. Although few T. minasense trypomastigotes were found in Giemsa-stained blood films from tamarins, a buffy-coat examination detected trypanosomes in 12 red-handed tamarins (80.0%), and PCR amplification of a highly variable region of the small subunit ribosomal RNA genes (SSU rDNA) for Trypanosoma spp. detected the infection in 14 of the 15 tamarins (93.3%). Nucleotide sequences of the amplicons were identical for trypanosomes from tamarins and squirrel monkeys, indicating a high prevalence but low parasitemia of T. minasense in imported Neotropical nonhuman primates. Based on the SSU rDNA and 5.8S rDNA, the molecular phylogenetic characterization of T. minasense indicated that T. minasense is closely related to trypanosomes with Trypanosoma theileri-like morphology and is distinct from Trypanosoma (Tejeraia) rangeli, as well as from T. cruzi. Using some blood samples from these monkeys, amplification and subsequent sequencing of the glycosomal glyceraldehyde-3-phosphate dehydrogenase (gGAPDH) gene fragments detected 4 trypanosome genotypes, including 2 types of T. cruzi clade, 1 type of T. rangeli clade, and 1 T. rangeli-related type, but failed to indicate its phylogenetic position based on the gGAPDH gene. Furthermore, species ordinarily classified in the Megatrypanum by morphological criteria do not form a clade in any molecular phylogenetic trees based on rDNA or gGAPDH genes.

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.

Wolbachia pipientis is a bacterial endosymbiont associated with arthropods and filarial nematodes. In filarial nematodes, W. pipientis has been shown to play an important role in the biology of the host and in the immuno-pathology of filariasis. Several species of filariae, including the most important parasites of humans and animals (e.g. Onchocerca volvulus, Wuchereria bancrofti and Dirofilaria immitis) have been shown to harbour these bacteria. Other filarial species, including an important rodent species (Acanthocheilonema viteae), which has been used as a model for the study of filariasis, do not appear to harbour these symbionts. There are still several open questions about the distribution of W. pipientis in filarial nematodes. Firstly the number of species examined is still limited. Secondly, it is not clear whether the absence of W. pipientis in negative species could represent an ancestral characteristic or the result of a secondary loss. Thirdly, several aspects of the phylogeny of filarial nematodes are still unclear and it is thus difficult to overlay the presence/absence of W. pipientis on a tree representing filarial evolution. Here we present the results of a PCR screening for W. pipientis in 16 species of filariae and related nematodes, representing different families/subfamilies. Evidence for the presence of W. pipientis is reported for five species examined for the first time (representing the genera Litomosoides, Litomosa and Dipetalonema); original results on the absence of this bacterium are reported for nine species; for the remaining two species, we have confirmed the absence of W. pipientis recently reported by other authors. In the positive species, the infecting W. pipientis bacteria have been identified through 16S rDNA gene sequence analysis. In addition to the screening for W. pipientis in 16 species, we have generated phylogenetic reconstructions based on mitochondrial gene sequences (12S rDNA; COI), including a total of 28 filarial species and related spirurid nematodes. The mapping of the presence/absence of W. pipientis on the trees generated indicates that these bacteria have possibly been lost during evolution along some lineages of filarial nematodes.