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The outbreak of yellow fever virus transmitted by Aedes aegypti has been of major concern in Nigeria, this mosquito also transmits several other arboviruses globally. The control of many vectors of mosquito-borne diseases relies heavily on the use of insecticides. Therefore, constant monitoring of insecticide resistance status and associated mechanisms is crucial within the local mosquito population. Here, we determined the resistance profile of adult Ae. aegypti from Majidun and Oke Ota communities, Ikorodu Local Government Area of Lagos State, Nigeria to different classes of insecticides using WHO procedures. The resistant phenotypes of Ae. aegypti were screened for the presence of kdr mutations F1534C, S989P, and V1016G, which have been implicated in insecticide resistance in yellow fever vectors. A high level of resistance to DDT and pyrethroids was recorded in Ae. aegypti in this study, although possible resistance to deltamethrin, one of the pyrethroids was reported in one of the locations. Resistance to bendiocarb was recorded in the Majidun community while Ae. aegypti in both locations were susceptible to malathion. The presence of F1534C mutation associated with DDT and deltamethrin resistance in Ae. aegypti population, and the presence of S989P mutation were detected singly and in co-occurrence with F1534C for the first time in Africa, while V1016G mutation was not detected in this study. The role of these mutations in resistance phenotype expressed in Ae. aegypti in larger populations needs to be established.

Discovering and developing the desired antimalarials continue to be a necessity especially due to treatment failures, drug resistance, limited availability and affordability of antimalarial drugs and costs especially in poor malarial endemic countries. This study investigated the efficacies of two plant cocktails; CtA and CtB, selected based on their traditional usage. Efficacies of the cocktail extracts, chloroquine and pyrimethamine against Plasmodium berghei berghei were evaluated in mice using the suppressive, curative and prophylactic test models, after oral and intraperitoneal acute toxicity determination of the plant cocktails in accordance with Lorke’s method. Data was analyzed using SPSS software version 23.0 with level of significance set at P

Mosquito breeding habitats play an important role in determining adult mosquitoes’ abundance and distribution. This study assessed the impact of physicochemical parameters of breeding water on Culex quinquefasciatus larval abundance. A larval survey was conducted in Epe, Eti-Osa, Kosofe, and Ojo local government areas (LGAs) of Lagos state. Emerged adults of Culex mosquitoes were identified. Members of the Cx. pipiens complex were identified into subspecies using polymerase chain reaction. Physicochemical parameters of water from larval sampling sites were analyzed using standard techniques. Six Culex species; Cx. quinquefasciatus, Cx. decens, Cx. nebulosus, Cx. cinereus, Cx. tigripes and Cx. duttoni were encountered. Cx. pipiens quinquefasciatus was the only member of the pipiens complex. Breeding habitat in Kosofe recorded the highest electrical conductivity, total dissolved solids (TDS), and nutrients followed by Ojo, Eti-Osa and then Epe. Larval densities were found to have significant relationship with ammonia (r = 0.507, p = 0.027) and sulfate (r = –0.539, p = 0.017) contents of the breeding habitats. The study revealed that Cx. p. quinquefasciatus is the most dominant and only member of the Cx. pipiens complex. Ammonia and sulfate have a significant impact on the abundance of Cx. quinquefasciatus immature stages. Manipulation of these two parameters could make Culex breeding water less suitable in the study areas.&nbsp

Malaria is of public health importance in Nigeria and may retain its status, if new intervention methods are not introduced or the current ones monitored. This study was carried out in Alimosho, Kosofe, Ibeju-Lekki and Badagry Local Government Areas (LGAs) of Lagos State to assess the susceptibility status of Anopheles gambiae s.l., a dominant malaria vector in the localities to DDT 4% and Permethrin 0.75%. Anopheles larvae were collected from larva habitats in both LGAs, reared to adults and fed with 10% sucrose solution. Nonblood fed 2-5 days old female mosquitoes were exposed to discriminating doses of DDT and permethrin according to the standard WHO procedures. The knockdown effect was recorded at interval of 10 minutes and mortality scored 24hours after exposure. Species identification was done by morphological characteristics. Results from the study showed that Anopheles gambiae s.l. are resistant to DDT (4%) and permethrin (0.75%) with 24hr post exposure mortality ranging from 15.00-24.0% and 4.25-22.0% respectively. The Knockdown Time (KDT) ranged from 30.8-941.95minutes for DDT and 12.6-85.51minutes for permethrin. KDT95 50 ranges from 117.49-27524.22 minutes and 117.49-412.1 minutes for DDT and permethrin respectively. All the LGAs showed high level of resistance to DDT and permethrin. The high level of insecticide resistance recorded in this study could be detrimental to the elimination of malaria. Therefore, integrated vector management is needed to effectively carry out to manage the development of insecticide resistance.

Introduction: Parasitic diseases are a major setback to sustainable poultry production. This study determined the occurrence of Eimeria species and haemosporidia among domestic chickens and helmeted guinea fowls in live-bird markets in Lagos State, Nigeria. Methods: Blood samples and intestinal contents at three distinct segments of the gut were collected from 60 domestic chickens and guinea fowls each. Wet smears of intestinal contents were microscopically examined for oocysts typical of Eimeria species while thin films of blood were Giemsa-stained for the demonstration of protozoa. Results: Results revealed that 19(31.7%) and 21(35%) chickens and guinea fowls w er e positive for Eimeria spp. infection respectively. There was no significant difference (P>0.05) in Eimeria spp. infections between the chicken breeds nor between sexes of both birds. Oocysts of Eimeria were mostly recovered from the caeca and small intestines of the guinea fowls and chickens respectively. Domestic chickens were infected with three different haemoprotozoa: Plasmodium spp. (23.3%), Leucocytozoon spp. (6.7%) and Haemoproteus spp. (3.3%); while Plasmodium spp. (15%) and Haemoproteus spp. (3.3%) were the only blood protozoa infecting guinea fowls. The infection rates of haemosporidia between the breeds of chickens and the sexes of both birds did not differ significantly (P>0.05). Conclusion: Eimeria parasites and haemosporidia are prevalent among chickens and guinea fowls sold in Lagos State. To prevent severe economic losses in the future, appropriate control measures should be designed and implemented.

Background Melanoides tuberculata is a freshwater snail that serves as an intermediate host for 11 parasitic flukes. This study was conducted with the aim of identifying and screening the snail intermediate hosts in the study site for schistosomiasis using the molecular technique. Methods DNA was extracted from the snails by the hexadecyl trimethyl ammonium bromide method and the Dra1 primer was used to amplify the Dra1 repeated sequence of Schistosoma haematobium. Results The presence of schistosome DNA in M. tuberculata by polymerase chain reaction was confirmed. Conclusions Our findings show that M. tuberculata is a potential intermediate host of schistosomes.

The knowledge of the ecology and abundance of mosquito is important in determining the potential risk of exposure to mosquito-borne diseases and the appropriate control measure to effectively reduce the mosquito population. A survey was carried out in four Local Government Areas (LGAs) of Lagos State, Nigeria for one year to determine the abundance, diversity, and larval habitat characteristics of mosquito. Larvae were collected using WHO standard methods, the physiochemical characteristics of the habitats were recorded, the larvae were reared to adults and identified using morphological identification keys and molecular assays. Adult mosquitoes were also collected outdoor using a trap with octanol attractant. Five species belonging to 3 genera were collected and identified as Anopheles gambiae complex, Anopheles funestus complex, Culex quinquefasciatus, Aedes aegypti, and Aedes albopictus. Cx quinquefasciatus (37.7%) is the most abundant followed by Ae aegypti (31.3%) and An. gambiae s.l. (26.9%) while Ae. albopictus (1.9%) is the least abundant. The larval abundance within the different species showed a high level of statistical significance (P

The development of resistance to some synthetic antimalarial drugs and the spread of counterfeit antimalarial drugs, has become a global problem. It has affected effective malaria treatment, making the development of new drugs exigent. Certain medicinal plants contain potent ingredients such as alkalloids, flavonoids, glycoside and volatile oils, which suppress the spread of plasmodial infections, and are widely used within the tropics for treatment of malaria. This study was designed to investigate the antiplasmodial activities of the combined aqueous extract of Morinda lucida, Phyllantus amarus, Vernonia amygdalina and Newbouldia laevis at variable doses in Swiss albino mice infected with Plasmodium berghei (NK65). Fifty mice were randomized into ten groups which were divided equally for suppressive and curative test. Four days suppressive and 5 days curative test were used to assess the antiplasmodial activities of the extract in mice infected with chloroquine sensitive P. berghei at concentration of 200mg/kg, 400mg/kg and 800mg/kg body weight. Furthermore the levels of aspartate aminotransferase (AST), alanine aminotransferase (ALT) and alkaline phosphate (ALP), urea and creatinin were determined by standard procedural methods to evaluate impact of extracts on hepatic and kidney function. The results of the 4 days suppressive test revealed that the test extract achieved percentage suppression of 9.8%, 58.3% and 60.2% for 200mg/kg, 400mg/kg and 800mg/kg concentration respectively. The curative test achieved the highest parasitaemia reduction with 800mg/kg (29.5±29.1 x 103) which was comparable to the standard antimalarial drug, chloroquine. There were significant elevation in the values of AST and ALT at 400mg/kg and 800mg/kg respectively suggesting hepatic dysfunction. However, ALP and urea showed no significant different (P>0.05), but creatinin showed significant difference (P

Pyrethroids and DDT are key insecticides in the control of malaria, yellow fever, and lymphatic filariasis vectors. Knockdown and metabolic resistance mechanisms have been proven to be important in determining the efficacy of insecticides. Here we investigated cytochrome P450 as a resistance mechanism in Anopheles gambiae Giles and Culex quinquefasciatus Say exposed to deltamethrin and DDT. Two- to three-days-old adult female mosquitoes were used for insecticide exposures and PBO synergistic assays using WHO standard guidelines, kits and test papers (DDT 4%, deltamethrin 0.05%, and PBO 4%). Polymerase chain reaction (PCR) assays were used for the identification of the species and for characterization of the kdr allele. Mortality at 24 h post-exposure was 18 and 17% in An. gambiae s.s. exposed to DDT and deltamethrin, respectively; 1 and 5% in Cx. quinquefasciatus exposed to DDT and deltamethrin respectively. Significant (P < 0.01) levels of susceptibility was recorded in mosquitoes pre-exposed to PBO, as KDT50 and 24 h of exposure ranged from 37.6 min to 663.4 min and 27 to 80%, respectively. Presence of a knockdown resistance allele was recorded in An. gambiae s.s., 22.5% for homozygote resistance and 7.5% for heterozygotes, while Cx. quinquefasciatus populations showed no kdr allele despite the high level of resistance to DDT and deltamethrin. Findings from this study indicated that cytochrome P450 mono-oxygenase expression is highly implicated in the resistance phenotype to DDT and pyrethroids in An. gambiae and Cx. quinquefasciatus in the study area.

Susceptibility and PBO synergist bioassays were done using 3–5 days old female Anopheles mosquito collected from Lagos State, Nigeria with WHO test papers DDT (4%), permethrin (0.75%), Bendiocarb (1%) and PBO (4%) according to standard procedures. The activities of cytochrome P450s, glutathione S-transferase and carboxylesterases were determined using biochemical assays. The presence of kdr-w, kdr-e and Ace-1R mutations were examined using molecular assays. Resistance to DDT and permethrin in An gambiae s.s from the four Local Government Areas (LGAs) was recorded while suspected resistance to bendiocarb was recorded in mosquitoes from Alimosho and Kosofe LGAs. PBO synergist reduced the knockdown time and also recorded significantly (P Kdr-w was detected in An. gambiae s.s from all the LGAs, kdr-e (L1014S) was detected in Alimosho, Kosofe and Ibeju-Lekki, while the Ace-1R gene was detected in Alimosho and Kosofe. Results from this study provide evidence for resistance of An. gambiae from Lagos State to multiple classes of neurotoxic insecticides with multiple resistance mechanisms to these insecticides.

This study evaluated the drinking water quality and associated human health risks in three (3) rural and urban areas each in Ibeju-Lekki and Epe local government areas of Lagos, Nigeria. Two hundre...

Background: Urinary schistosomiasis is endemic in many rural communities of Nigeria and school aged children are mostly affected. A cross-sectional study was carried out to assess the prevalence and intensity of urinary schistosomiasis infection among 251 school aged children in two communities of Ovia South West LGA of Edo State, Nigeria, as well as their knowledge on the control/elimination measures. Methods: Urine samples were collected and examined by microscopy using filtration technique. In addition, a questionnaire survey was conducted among school-aged children and health care providers, probing their knowledge, attitude and practices on on-going control activities. Results: The prevalence of urinary schistosomiasis among the school-aged children was 65.3%. The prevalence was generally higher among females (68.8%) and children in the age groups 10–14 (69.9%). The intensity of infection ranged from 1 to 5044 (mean = 449.8) eggs/10 ml of urine with a higher proportion having heavy infections (76.8%, P

Background Asymptomatic malaria parasites are significant sources of infections for onward malaria transmission. Conventional tools for malaria diagnosis such as microscopy and rapid diagnostic test kits (RDT) have relatively low sensitivity, hence the need for alternative tools for active screening of such low-density infections. Methods This study tested var acidic terminal sequence-based (varATS) quantitative polymerase chain reaction (qPCR) for screening asymptomatic Plasmodium falciparum infections among dwellers of a sub-urban community in Lagos, Nigeria. Clinically healthy participants were screened for malaria using microscopy, RDT and varATS qPCR techniques. Participants were stratified into three age groups: 1–5, 6–14 and > 14 years old. Results Of the 316 participants screened for asymptomatic malaria infection, 78 (24.68%) were positive by microscopy, 99 (31.33%) were positive by RDT and 112 (35.44%) by varATS qPCR. Participants aged 6–14 years had the highest prevalence of asymptomatic malaria, with geometric means of ~ 116 parasites/µL and ~ 6689 parasites/µL as detected by microscopy and varATS, respectively. Conclusion This study has revealed high prevalence of asymptomatic malaria in the study population, with varATS detecting additional sub-microscopic infections. The highest concentration of asymptomatic malaria was observed among school-age children between 6 and 14 years old. A large-scale screening to identify other potential hotspots of asymptomatic parasites in the country is recommended.

Diversity amongst the different populations is one of the problems in the control of medically important mosquitoes. Wing morphometry was used to identify within-species variation amongst some populations ofAedes aegyptiin three areas of Lagos State, Nigeria. Ten landmarks on the right wing of adult femaleAe. aegyptimosquitoes were digitized using TPSdig software. Relative distances of the veins and interpoints were calculated as well as the Euclidean distances based on these relative distances. In three (50%) of the interpoints, the relative distances were significant (PAe. aegyptiwere identified, and the differences in lengths and interpoints observed on the wing veins suggest a possible morphological divergence amongst populations.

Introduction: Extensive genetic diversity of malaria parasites is a major draw back to ongoing control efforts. Population-specific investigation of genetic structure of the parasite is important for effective malaria intervention in endemic populations such as Nigeria where about one-third of the global burden of the disease is borne. This study describes the genetic diversity of Plasmodium falciparum isolates in the Niger River basins, North-Central Nigeria. Methodology: Parasite DNA w as extracted fr om finger -prick blood samples collected from eighty P. falciparum positive individuals. Polymerase Chain Reaction (PCR) genotyping was carried out to target K1, MAD20 and R033 allelic families of Merozoite Surface Protein (MSP) -1 gene and FC27 and 3D7 allelic families of MSP-2 gene. Results: Proportion of isolates with K1 family w as 28(70%) with two alleles in Idah and 16(40%) with two alleles in Ibaji. Proportion of isolates with MAD20 family was 8 (20%) and a total of two alleles were observed in Idah and 4(10%) with two alleles in Ibaji. RO33 proportion was 16 (40%) in Idah one allele and 8(20%) in Ibaji where the allelic family was also observed to be monomorphic. K1 was the most predominant MSP1 allele in the two parasite populations and the frequency of FC27 genotype was higher than 3D7 in both populations. Multiplicity of infection (Mol) with MSP-1 loci was higher in Ibaji (1.30) than Idah (1.05) while MoI with MSP-2 loci was lower in Ibaji (2.00) than Idah (2.13). However, there is no significant difference in the mean Mol between Idah and Ibaji (P > 0.05). The expected heterozygosity (HE) value was 0.56 for MSP-1 and 0.84 for MSP-2. Conclusion: Our findings revealed high levels of monoclonal infections with P. falciparum, suggesting low parasite diversity. This may be a pointer to a reduction in malaria transmission in the river basins.

Background The decline in the efficacy of artemisinin-based combination treatment (ACT) in some endemic regions threatens the progress towards global elimination of malaria. Molecular surveillance of drug resistance in malaria-endemic regions is vital to detect the emergence and spread of mutant strains. Methods We observed 89 malaria patients for the efficacy of artemether-lumefantrine for the treatment of uncomplicated Plasmodium falciparum infections in Lagos, Nigeria and determined the prevalence of drug resistant strains in the population. Parasite clearance rates were determined by microscopy and the highly sensitive var gene acidic terminal sequence (varATS) polymerase chain reaction for 65 patients with samples on days 0, 1, 3, 7, 14, 21 and 28 after commencement of treatment. The genomic finger print of parasite DNA from pre- and post-treatment samples were determined using 24 nuclear single nucleotide polymorphisms (SNP) barcode for P. falciparum. Drug resistance associated alleles in chloroquine resistance transporter gene (crt-76), multidrug resistance genes (mdr1–86 and mdr1–184), dihydropteroate synthase (dhps-540), dihydrofolate reductase (dhfr-108) and kelch domain (K-13580) were genotyped by high resolution melt analysis of polymerase chain reaction (PCR) fragments. Results By varATS qPCR, 12 (18.5%) of the participants had detectable parasite DNA in their blood three days after treatment, while eight (12.3%) individuals presented with genotypable day 28 parasitaemia. Complexity of infection (CoI) was 1.30 on day 0 and 1.34 on day 28, the mean expected heterozygosity (HE) values across all barcodes were 0.50 ± 0.05 and 0.56 ± 0.05 on days 0 and 28 respectively. Barcode (π) pairwise comparisons showed high genetic relatedness of day 0 and day 28 parasite isolates in three (37.5%) of the eight individuals who presented with re-appearing infections. Crt-76 mutant allele was present in 38 (58.5%) isolates. The mdr1–86 mutant allele was found in 56 (86.2%) isolates. No mutation in the K-13580 was observed. Conclusions Persistence of DNA-detectable parasitaemia in more than 18% of cases after treatment and indications of genetic relatedness between pre- and post-treatment infections warrants further investigation of a larger population for signs of reduced ACT efficacy in Nigeria. Electronic supplementary material The online version of this article (10.1186/s12879-018-3314-3) contains supplementary material, which is available to authorized users.

Schistosomiasis, a major public health challenge is caused by trematodes of the genus Schistosoma whose intermediate host is snails. Sub-Saharan African (SSA) carried 85% of the global burden of this infection principally amongst school age children. Similarly, Nigeria bears the highest weight of this highly preventable infection in SSA. Preventive chemotherapy (PC) with 40-60 mg\kg praziquantel (PZQ) annually is the focal control strategy in endemic areas. Despite more than two decades of PZQ usage in Nigeria, the disease is still prevalent in affected communities. Thus, the study sought to assess the current post-treatment efficacy of PZQ use for urinary schistosomiasis among primary school age children of Ipogun village. Urine reagent strip (Haemastix) ® was initially used to screen pupils for haematuria, while Kato-Katz and urine filtration were employed to confirm the presence of schistosome ova in the faeces and urine of the study population pre- and post-treatment. A total of 202 children were screened, out of which 117 (57.9%) were positive for microhaematuria and 91 (45.0%) had ova of Schistosoma haematobium in their urine. The 14 and 21 day post-treatment assessment revealed 73.6% and 23.1% of the initially infected children to still be with infection respectively. Additionally, there was a statistical significant ( P =0.02) in the reduction of egg count twenty-one days post-treatment. Though the efficacy of the drug as observed in the egg reduction rate in the study area can be classified as satisfactory, continuous monitoring of schistosome response should not cease if the global target of eliminating morbidity due to schistosomiasis by year 2020 is to be achieved. © 2018 International Formulae Group. All rights reserved. Keywords: preventive chemotherapy, egg reduction rate, elimination, morbidity, microhaematuria

Background : Lime extracts of powdered combination of seeds of Picralima nitida, stem bark of Alstonia boonei and leaves of Gongronema latifolium is a common remedy used in the treatment of malaria in South Western Nigeria. Objective : To determine the antiplasmodial activities of the combined herbal extracts and its impact on the haematological, hepatological and renological parameters in mice. Methods : The 4-day suppressive and curative tests were used to assess the antiplasmodial activities of the extract in mice infected with chloroquine-sensitive Plasmodium berghei at concentration of 200mg/kg, 400mg/kg and 800mg/kg body weight. The haematological parameters including red blood cells, white blood cells, packed cell volume and haemoglobin count were analysed with an auto analyser. The activities of alanine aminotransferase (ALT), aspartate aminotransferase (AST) and alkaline phosphatase (ALP) were determined, while urea, protein and creatinine were analysed by standard procedural methods. Results : The 4-day suppressive test revealed that the test extract achieved percentage suppression of 39.0%, 41.6% and 54.68% for the 200mg/kg, 400mg/kg and 800mg/kg concentration respectively. Additionally, the curative test achieved a high percentage suppression of 80.97%, 83.84% and 86.16% at the 200mg/kg, 400mg/kg and 800mg/kg concentration respectively. The extracts did not induce significant change on haematological parameters (P>0.05), while significant elevation in the values of the ALT and AST (P

Background Resistance monitoring is essential in ensuring the success of insecticide based vector control programmes. This study was carried out to assess the susceptibility status of urban populations of Anopheles gambiae to carbamate insecticide being considered for vector control in mosquito populations previously reported to be resistant to DDT and permethrin. Methods Two – three day old adult female Anopheles mosquitoes reared from larval collections in 11 study sites from Local Government Areas of Lagos were exposed to test papers impregnated with DDT 4%, deltamethrin 0.05% and propoxur 0.1% insecticides. Additional tests were carried out to determine the susceptibility status of the Anopheles gambiae population to bendiocarb insecticide. Members of the A. gambiae complex, the molecular forms, were identified by PCR assays. The involvement of metabolic enzymes in carbamate resistance was assessed using Piperonyl butoxide (PBO) synergist assays. The presence of kdr-w/e and ace-1R point mutations responsible for DDT-pyrethroid and carbamate resistance mechanisms was also investigated by PCR. Results Propoxur resistance was found in 10 out of the 11 study sites. Resistance to three classes of insecticides was observed in five urban localities. Mortality rates in mosquitoes exposed to deltamethrin and propoxur did not show any significant difference (P > 0.05) but was significantly higher (P A. gambiae s.s (M form). The kdr -w point mutation at allelic frequencies between 45%-77% was identified as one of the resistant mechanisms responsible for DDT and pyrethroid resistance. Ace-1R point mutation was absent in the carbamate resistant population. However, the possible involvement of metabolic resistance was confirmed by synergistic assays conducted. Conclusion Evidence of carbamate resistance in A. gambiae populations already harbouring resistance to DDT and permethrin is a clear indication that calls for the implementation of insecticide resistance management strategies to combat the multiple resistance identified.

Mosquito samples were collected from rural and urban communities in three selected major towns in Southwestern Nigeria to determine the impact of urbanization on the diversity and abundance of Anopheles species associated with malaria transmission in human habitations. A total of ten Anopheles species were identified in the rural communities, while eight Anopheles species were identified in the urban communities. Out of the ten Anopheles species identified, only four species, Anopheles gambiae (Giles), Anopheles funestus (Giles), Anopheles moucheti (Evans), and Anopheles nili (Theobald), were established to be vectors of malaria occurring in greater than 50 % of the rural communities. Only A. gambiae occurred in all the urban communities, while the other three major vectors occurred in not more than 20 % of the urban communities. Margalef's and Shannon–Wiener indices showed that diversity and species richness were higher in the rural compared to the urban. Comprehensive information on malaria vector abundance and diversity in rapidly changing communities is an important tool in planning and implementing successful vector control programs.

Current efforts at controlling parasitic disease entail prior rapid diagnosis of the infection communities and individuals before intervention. Onchocerciasis is a major public health problem in Nigeria that is receiving quality attention through mass annual treatment with ivermectin. The fact that most affected communities are difficult to reach necessitated a search for the most appropriate approach at reaching them. It is in this respect that the World Health Organization (WHO) developed the Community Directed Treatment approach in mass treatment of the disease. This had enabled previously neglected by highly needy communities to benefits from control programme irrespective of literacy level and health infrastructure. According to drug manufactures, weight is usually the means to determine dosage but given the difficulty associated with the use and availability of weighting scales in most onchocerciasis affected communities in a Community Director approach to treatment, the use of height, which is far easier to comprehended and use have been adopted in onchocerciasis control. The aim of the present study is to compare the height with the use of height with the use of weight for dose determination in ivermectin delivery. 55.1 individuals of Ipogun community in Ifedore Local Government Area of Ondo State, comprising 269 males (49%) and 282 females (51%), who received ivermectin based on height measurement using calibrated measuring sticks were weighed. The weights were used to calculate the number of ivermectin tablets the individuals would have received if the dose had been based on eight. A person statistical test was carried out to measure the relationship. A correlation coefficient of r=0.89 was obtained for height and weight schedule. A total of 893 tablets were used in the treatment exercise based on the dosage by height whereas 744 tablets would have been needed if weight had been to determine dosage. The implications of these are discussed. NQJHM Vol. 13 (3-4) 2003: pp. 69-74

The natural arthropod and helminth infections of a vast colony of a West African fruit batEidolon helvum were studied over a period of 2 years. The seasonal prevalence of a non-specific ectoparasiteCyclopodia greeffi Karsch, 1884 is presented, while the complete absence of endoparasitic infection in the gut is noted. A single helminth infection withConcinnum epomopis Sandground, 1937 (Digenea) in the pancreas was found. This digenean is redescribed and data on the occurrence is presented. Helminth infection as a means of population control of the fruit bat is ruled out, as infections appeared to be accidental; the factors determining the prevalence and frequency of infections are considered. The significant factors responsible for the general overall poor helminth fauna of fruit bats in comparison to the generally diverse helminth fauna of the local insectivorous bats are discussed. Histopathological changes resulting from infection are recorded.

A detailed study of the surface topography ofConcinnum epomopis (Dicrocoeliidae) was carried out with a scanning electron microscope. The ultrastructural observations demonstrate the absence of spines on the body surface; however, the tegument is complex, exhibiting distinct, minute, lateral undulations, predominantly on the ventral side. The pattern of the tegumentary lamellae in different regions of the body is described. Two types of sensory papillae, the pit-type and the aciliate dome-type exhibit a uniform and distinct pattern of distribution on the surface of the worm. The pit-type is limited to the ventral depression anterior to the oral sucker. The pre-acetabular ventral genital opening, the posterior terminal excretory pore and pre-equatorial opening of the Laurer's canal are devoid of structural specialization and sensory papillae. The cylindrical, everted cirrus is covered with anastomosing, longitudinal lamellae of tegument, between which lie minute aggregates of protuberances forming the cirral papillae.

SUMMARYThe reproductive duct of the male blood fluke Schistosoma mansoni is relatively short and undulating, extending from the most posterior testis to the beginning of the gynecophoric canal. The reproductive duct may be divided into 3 main regions which differ in ultrastructure; the vas efferens/deferens, the seminal vesicle and the cirrus tube. The epithelium of the vas efferens/deferens consists of a single layer of elongate cells with abundant convoluted lamellae on their apical surfaces. The wall of the seminal vesicle and the cirrus tube are tegumentary in nature. The basic similarities in structure of the surface tegument, the seminal vesicle and the cirrus tube suggest a common embryological origin. The presence of complex lamellae on the luminal surface suggests that the vas efferens and deferens have secretory and possibly nutritive functions apart from temporarily storing developing germ cells. The primary function of the seminal vesicle appears to be that of sperm storage; while the cirrus tube with its complex infolded wall is extensible for insemination. The presence of abundant concentrically distributed sensory papillae around the male genital pore may assist in the pairing of males and females.

Astiban produced structural damage in male Schistosoma mansoni (Puerto Rican strain) in mice. The degree of disorganization was directly related to the dosage administered, although initial changes in structure for the first three doses (3 × 30–40 mg/kg) varied between individual worms of the same infection. More consistent damage to the tegument, parenchyma, and reproductive organs occurred after 6 × 40 mg/kg of Astiban injections. Exposure of the subtegumentary musculature preceded appearance of an increased number of noncytoplasmic spaces in various tissues, probably a result of osmotic stress. Testicular disorganization was prominent initially in spermatozoa and spermatids, but became more generalized with drug accumulation. The sustentacular cells showed increased phagocytic activity with testicular damage. Continuous administration of drug resulted in a general distortion of the worm's morphology. However, partial recovery occurred within 22 days following cessation of drug administration.

SUMMARYStudies on the multiple compact testes of Schistosoma mansoni have revealed 2 principal cell types: germinal and non-germinal cells. Two morphological forms representing different stages in the cytomorphosis of the sustentacular cells have been considered. The polymorphic sustentacular cells which are conspicuously stained with potassium permanganate contain abundant ribosomal endoplasmic reticulum, glycogen particles and ribosomal masses in comparison with the germinal component of the testes. Golgi complexes with associated secretory bodies and vacuoles are present in the cells. The cytoplasm of the sustentacular cells interdigitate between other cells in the testes. Based on their morphology, nutritive, supportive and phagocytic functions have been attributed to the sustentacular cells. The possible recycling of nutrients by the cells is discussed. It is suggested that the cells regulate the production of spermatozoa from a nutritive viewpoint and also that the translocation of nutrients from the parenchyma to the testes is facilitated by these cells whose cytoplasm extends directly adjacent to the basal lamina.

Background: Genetic diversity studies provide evidence of Plasmodium falciparum differentiation that could affect fitness and adaptation to drugs and target antigens for vaccine development. This study describes the genetic structure of P. falciparum populations in urban and rural sites from southwestern Nigeria. Methodology: Ten neutral microsatellite loci were genotyped in 196 P. falciparum infections from three localities: Aramoko-Ekiti, a rural community; Lekki, an urban location and Badagry, a peri-urban border settlement. Analysis was performed on the genetic diversity, linkage disequilibrium, population structure and inter-population differentiation. Results: Allelic diversity values were similar across all populations, with mean expected heterozygosity (HE )v alues between 0.65 and 0.79. No matching multilocus haplotypes were found and analysis of multilocus LD showed no significant index of association. Genetic differentiation between populations was low (ΦPT=0.017). Conclusion: The absence of detectable population structure of P. falciparum in southwestern Nigeria is evident in the lack of significant differentiation between populations separated by about 200 km. This implies that a fairly uniform malaria control strategy may be effective over a wide geographic range in this highly endemic region. However, more wide-scale survey across the country will be required to inform malaria control in this large and densely populated endemic region.