Population Genetic Structure and Hybridization of Schistosoma haematobium in Nigeria.

Background: Schistosomiasis is a major poverty-related disease caused by dioecious parasitic flatworms of the genus Schistosoma with a health impact on both humans and animals. Hybrids of human urogenital schistosome and bovine intestinal schistosome have been reported in humans in several of Nigeria's neighboring West African countries. No empirical studies have been carried out on the genomic diversity of Schistosoma haematobium in Nigeria. Here, we present novel data on the presence and prevalence of hybrids and the population genetic structure of S. haematobium. Methods: 165 Schistosoma-positive urine samples were obtained from 12 sampling sites in Nigeria. Schistosoma haematobium eggs from each sample were hatched and each individual miracidium was picked and preserved in Whatman® FTA cards for genomic analysis. Approximately 1364 parasites were molecularly characterized by rapid diagnostic multiplex polymerase chain reaction (RD-PCR) for mitochondrial DNA gene (Cox1 mtDNA) and a subset of 1136 miracidia were genotyped using a panel of 18 microsatellite markers. Results: No significant difference was observed in the population genetic diversity (p > 0.05), though a significant difference was observed in the allelic richness of the sites except sites 7, 8, and 9 (p < 0.05). Moreover, we observed two clusters of populations: west (populations 1−4) and east (populations 7−12). Of the 1364 miracidia genotyped, 1212 (89%) showed an S. bovis Cox1 profile and 152 (11%) showed an S. haematobium cox1 profile. All parasites showed an S. bovis Cox1 profile except for some at sites 3 and 4. Schistosoma miracidia full genotyping showed 59.3% of the S. bovis ITS2 allele. Conclusions: This study provides novel insight into hybridization and population genetic structure of S. haematobium in Nigeria. Our findings suggest that S. haematobium x S. bovis hybrids are common in Nigeria. More genomic studies on both human- and animal-infecting parasites are needed to ascertain the role of animals in schistosome transmission.

Data on heavy metals content and biochar toxicity in a pristine tropical agricultural soil.

Accumulation of heavy metals results in soil degradation and impairs the normal functioning of ecosystems. Thus, monitoring of heavy metals is essential in both pristine and polluted soils. Concentrations of heavy metals were determined in a pristine tropical agricultural soil using acid digestion procedures. The soil samples were also analyzed for physico-chemical parameters and biochar toxicity to earthworms. Data shows that the soil is acidic, with low organic matter content. The level of heavy metals ranged from <0.06±0.0 to 595.8±2.8 µg g-1. However, the concentrations were found to be below the soil regulatory standards of heavy metals in agricultural soils. Furthermore, increased addition of biochar to the soil caused toxic effect on earthworms over a 90 d biochar-soil contact time. The data provides baseline information of heavy metals in pristine agricultural soils from the region, and the effect of biochar amendments on tropical soils.

Influence of biochar aged in acidic soil on ecosystem engineers and two tropical agricultural plants.

Biochar amendment to soil is predicted globally as a means to enhance soil health. Alongside the beneficial result on soil nutrient availability and retention, biochar is presumed to increase soil macro / microbiota composition and improve plant growth. However, evidence for such an effect remains elusive in many tropical agricultural soils. The influence of biochar aged in soil was assessed on soil microbiota, macrobiota (Eudrilus eugeniae), seedling emergence and early plant growth of Oryza sativa and Solanum lycopersicum in tropical agricultural soil, over a 90 d biochar-soil contact time. Results showed negative impacts of increased loading of biochar on the survival and growth of E. eugeniae. LC50 and EC50 values ranged from 34.8% to 86.8% and 0.9-23.7% dry biochar kg-1 soil, over time. The growth of the exposed earthworms was strongly reduced (R2 = -0.866, p < 0.05). Biochar significantly increased microbiota abundance relative to the control soil (p < 0.001). However, fungal population was reduced by biochar addition. Biochar application threshold of 10% and 5% was observed for (O. sativa) and (S. lycopersicum), respectively. Furthermore, the addition of biochar to soil resulted in increased aboveground (shoot) biomass (p < 0.01). However, the data revealed that biochar did not increase the belowground (root) biomass of the plant species during the 90 d biochar-soil contact time. The shoot-to-root-biomass increase indicates a direct toxic influence of biochar on plant roots. This reveals that nutrient availability is not the only mechanism involved in biota-biochar interactions. Detailed studies on specific biota-plant-responses to biochars between tropical, temperate and boreal environments are needed to resolve the large variations and mechanisms behind these effects.

Evaluation of the utility value of three diagnostic methods in the detection of malaria parasites in endemic area.

BACKGROUND: Malaria is a debilitating disease with high morbidity and mortality in Africa, commonly caused by different species of the genus Plasmodium in humans. Misdiagnosis is a major challenge in endemic areas because of other disease complications and technical expertise of the medical laboratory staff. Microscopic method using Giemsa-stained blood film has been the mainstay of diagnosis of malaria. However, since 1993 when rapid diagnostic test (RDT) kits were introduced, they have proved to be effective in the diagnosis of malaria. This study was aimed at comparing the accuracy of microscopy and RDTs in the diagnosis of malaria using nested PCR as the reference standard. Four hundred and twenty (420) venous blood specimens were collected from patients attending different General Hospitals in Ebonyi State with clinical symptoms of malaria. The samples were tested with Giemsa-stained microscopy and three RDTs. Fifty specimens were randomly selected for molecular analysis. RESULTS: Using different diagnostic methods, the prevalence of malaria among the subjects studied was 25.95% as detected by microscopy, prevalence found among the RDTs was 22.90, 15.20 and 54.80% for Carestart, SD Bioline PF and SD Bioline PF/PV, respectively. Molecular assay yielded a prevalence of 32%. The major specie identified was Plasmodium falciparum; there was co-infection of P. falciparum with Plasmodium malariae and Plasmodium ovale. The sensitivity and specificity of microscopy was 50.00 and 70.59% while that of the RDTs were (25.00 and 85.29%), (25.00 and 94.12%) and (68.75 and 52.94%) for Carestart, SD Bioline PF and SD Bioline PF/PV, respectively. Cohen's kappa coefficient was used to measure the level of agreement of the methods with nested PCR. Microscopy showed a moderate measure of agreement (k = 0.491), Carestart showed a good measure of agreement (k = 0.611), SD Bioline PF showed a fair measure of agreement (k = 0.226) while SD Bioline PF/PV showed a poor measure of agreement (k = 0.172). CONCLUSIONS: This study recommends that the policy of malaria diagnosis be changed such that the routine diagnosis of malaria is done by a combination of both microscopy and a RDT kit of high sensitivity and specificity so as to complement the errors associated with either of the methods. The finding of P. ovale in the study area necessitates an expanded molecular epidemiology of malaria within the study area.

DISTRIBUTION AND UTILISATION OF IVERMECTIN (MECTIZAN): A CHEMOTHERAPEUTIC APPROACH TO THE CONTROL OF ONCHOCERCIASIS IN OLD OHAOZARA LGA, EBONYI STATE, EASTERN NIGERIA.

Onchocerciasis (river blindness) is a devastating, debilitating Stigmatising and incapacitating parasitic disease that is endemic in tropical and subtropical regions of the world, including Nigeria. Mass distribution of ivermectin (Mectizan) to the endemic parts of the world was initiated by the Onchocerciasis Control Programmes (OCPs). Absolute compliance to the regimen for up to 15 years has been reported to be effective in the control of the disease. The study was carried out in Ohaozara LGA, Onicha LGA and Ivo LGA. The three (3) LGAs made up the defunct Old Ohaozara LGA. A structured questionnaire was used to generate information on knowledge of Onchocerciasis and on the use of ivermectin by the inhabitants of the communities of the study areas. The distribution coverage of ivermectin in the study areas dating from 2010 to 2014 was ascertained with drug distribution charts obtained from Ebonyi State Health Management Board (ESHMB), Abakaliki (the point source of distribution in the state), and from the health centres in communities of old Ohaozara LGA (the service delivery points (SDPs) to inhabitants of the communities. Data was analysed using descriptive statistics. Utilization of the regimen was ascertained by determining the actual number of tablets of mectizan that was administered to the patients at the various health cenrtes (service delivery points (SDPs) in the communities. The percentage utilization of the regimen was determined by dividing the number of mectizan tablets administered to the patients at SDPs with the number of mectizan tablets supplied from state point source of distribution and multiplying by 100. A total of 347, 299 out of 1, 919135 tablets of mectizan supplied to the study areas from 2010 to 2014 were actually utilized, forming an overall percentage utilization of 18.10%. There was adequate supply but very poor utilization of the regimen. The poor utilization resulted from factors including locating of health centres very far from homes of some of the rural villagers, non-yearly compliance with regimen administration, poor health sensitization and education and lack of incentives orpoor incentives to the village-based health workers (VBHWs). Intensification of efforts to cover the lapses in the utilization of the regimen is advocated for a more effective control of the disease.

Western blot-indeterminate results in Nigerian patients HIV serodiagnosis: the clinical and public health implication.

The clinical and public health implication of HIV Western blot (WB) indeterminate results is yet to be appraised in sub-Saharan Africa, including Nigeria. Using HIV Tri Line Test enzyme-linked immunosorbent assay (ELISA), 1286 patients (600 males and 686 females; age range, 5-60 years) with symptoms suggestive of HIV infection were screened. A total of 1020 (79.3%, 95% confidence interval [CI] 76.8-81.5) of the patients comprising of 514 (85.7%) males and 506 (73.8%) females were HIV seropositive and the difference was statistical significantly (chi(2) = 5.72, df = 1, p < 0.05). Western blot analysis of sera from the 1020 HIV-seropositive individuals using the BIO-RAD NEW LAV-BLOT I specifying World Health Organization (WHO) interpretive criteria, confirmed the HIV serostatus of 815 (79.9%, 95% CI, 77.4-82.4) of them with 205 (20.1%, 95% CI, 17.6-22.6) individuals having indeterminate results consisting of either; 1 env +/- gag +/- pol, gag + pol, gag only or pol only. Of these, 102 (19.8%) were males and 103 (20.4%) were females. Patients aged 11-20 years old recorded the highest percentage of indeterminate results (31.7%, 95% CI, 20.2-43.2) while those aged 21-30 years recorded the least (14.2%, 95% CI, 10.6-17.8) and the difference was statistically significant (chi(2) = 15.73, df = 5, p < 0.05). Result confirmed the limitation of Western blot assays in HIV confirmatory serodiagnosis. After obtaining HIV indeterminate Western blot result, clinicians should consider the total profile for the patient, reassess risk factors for HIV infection, perform a HIV retesting at 3-month intervals for 6 months or use an alternate HIV antibody confirmatory assay and running antibody tests for other human retroviruses.