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Abstract Background Studies on biting behaviours and infectivity status of insect vectors are pre-requisites in understanding the epidemiology of the vector- borne diseases and planning effective control measures. A longitudinal study was carried out to investigate the transmission index of Simulium damnosum complex species along Osun River, South Western Nigeria. Adult flies were collected on human attractants from 07:00 to 18:00 hours for two consecutive days from February 2008 to June 2009 at three communities: Osun Eleja, Osun Ogbere and Osun Budepo. The infectivity rate was determined by dissection and Polymerase Chain Reaction amplification (PCR) of 0-150 genes of Onchocerca parasite using the pool screening technique. Results The results indicated that the majority of the flies collected at the three sampling points were nulliparous as they accounted for 53.90%, 57.86% and 59.58% of the flies dissected at Osun Budepo, Osun Ogbere and Osun Eleja, respectively. The parous rate was higher during the dry season than the wet season but the difference was not statistically significant (p < 0.05). The biting activity of the parous flies showed two peaks at Osun Budepo and three peaks at Osun Eleja and Osun Ogbere. Of the 1,472 flies dissected and 1,235 flies screened by molecular method, none was infected with Onchocerca parasite at the three sampling points however the annual biting rates at the three communities were higher than 1,000 considered as tolerable value for a person living in an onchocerciasis zone by Word Health Organization. Conclusion The study has provided the baseline data for further study on onchocerciasis transmission dynamics and the need to intercept man- simuliid vector contact at the study area.

Abstract Background The control of schistosomiasis in Nigeria is mainly by mass treatment with praziquantel through the school system, with an absence of any provision for pre-school children. We therefore determined the prevalence and intensity of urinary schistosomiasis in pre-school children between the ages of 1-6 years in Ilewo-Orile a rural and endemic community, near Abeokuta, Nigeria as part of providing information on the neglected tropical diseases among this age group. Two urine samples were collected from each pre-school child. The samples were tested for microhaematuria using reagent strips and then processed and examined with a microscope for Schistosoma haematobium ova. Results Of the 167 children examined 97 (58.1%) had infection, with no significant difference (P = 0.809) in infection rates between boys (57.1%) and girls (59.2%). Both prevalence and intensity of infection did not increase significantly with age (P = 0.732). The overall geometric mean egg count was 1.17 eggs/10 ml urine. There was no significant association (P = 0.387) between intensity in boys (1.16 eggs/10 ml urine) and girls (1.19 eggs/10 ml urine). 47.4% of the children had microhaematuria which did not increase significantly with age (P = 0.526). Focus group discussions with guardians and caregivers revealed that infection of pre-school children early in life was due to exposures through bathing in the stream by their mothers, while the older children would visit the stream for washing, fetching of water, bathing and swimming. Conclusion Community participatory health education is needed in this community as a first step in reducing infection and transmission of the disease, while the rehabilitation and repair of the existing water borehole system in the community should be effected. The results of this study have shown that pre-school children also harbour infection and are a source of transmission of schistosomiasis in endemic communities. Planning and provision for their treatment should be considered in control programmes.

Abstract Background Simulum damnosum Theobald sensu lato (s.l.) is the vector of the parasitic filarial worm Onchocerca volvulus Leuckart which causes onchocerciasis. In order to understand the vector population dynamics, a preliminary 12 months entomological evaluation was carried out at Abeokuta, the Southwest Zone of Nigeria, an onchocerciasis endemic area, where vector control has not been previously initiated. S.damnosum s.l. flies were caught on human attractants between 700 to1800 hours each day, for 4 days each month, from August 2007 to July 2008. The flies caught were classified as either forest-dwelling or savanna-dwelling groups based on the colour of certain morphological characters. Climatic data such as rainfall, humidity and temperature were also collected monthly during the period of survey. Results A total of 1,139 flies were caught, 596 (52.33%) were forest-dwelling group while 543 (47.67%) were savanna-dwelling group of S. damnosum s.l. The highest percentage of forest-dwelling group was caught in the month of August 2007 (78.06%) and the least percentage of forest-dwelling groups was caught in November 2007 (8.14%). The highest percentage of savannah-dwelling group was caught in the month of November 2007 (91.86%) and the least percentage of savannah-dwelling group was caught in August 2007 (21.94%). There was no significant difference between the population of forest and savannah-dwelling groups of the fly when the means of the fly population were compared (P = 0.830). Spearman correlation analysis showed a significant relationship between monthly fly population with monthly average rainfall (r = 0.550, n = 12, P = 0.033), but no significant relationship with monthly average temperature (r = 0.291, n = 12, P = 0.179). There was also a significant relationship between monthly fly population and monthly average relative humidity (r = 0.783, n = 12 P = 0.001). There was no significant correlation between the population of forest-dwelling group of S. damnosum s.l. and monthly average rainfall (r = 0.466, n = 12, P = 0.064) and monthly average temperature (r = 0.375, n = 12, P = 0.115) but there was significant correlation with monthly average relative humidity (r = 0.69, n = 12, P = 0.006). There was significant correlation between savannah-dwelling group and monthly average rainfall (r = 0.547, n = 12, P = 0.033), and monthly average relative humidity (r = 0.504, n = 12, P = 0.047) but there was no significant correlation with monthly average temperature (r = 0.142, n = 12, P = 0.329) Conclusion The results from this study showed that both the forest and the savannah dwelling groups of S. damnosum s.l. were caught biting in the study area. This could have implications on the transmission and epidemiology of human onchocerciasis if not monitored.

Abstract Background The control of urinary schistosomiasis in Ogun State, Nigeria remains inert due to lack of reliable data on the geographical distribution of the disease and the population at risk. To help in developing a control programme, delineating areas of risk, geographical information system and remotely sensed environmental images were used to developed predictive risk maps of the probability of occurrence of the disease and quantify the risk for infection in Ogun State, Nigeria. Methods Infection data used were derived from carefully validated morbidity questionnaires among primary school children in 2001–2002, in which school children were asked among other questions if they have experienced "blood in urine" or urinary schistosomiasis. The infection data from 1,092 schools together with remotely sensed environmental data such as rainfall, vegetation, temperature, soil-types, altitude and land cover were analysis using binary logistic regression models to identify environmental features that influence the spatial distribution of the disease. The final regression equations were then used in Arc View 3.2a GIS software to generate predictive risk maps of the distribution of the disease and population at risk in the state. Results Logistic regression analysis shows that the only significant environmental variable in predicting the presence and absence of urinary schistosomiasis in any area of the State was Land Surface Temperature (LST) (B = 0.308, p = 0.013). While LST (B = -0.478, p = 0.035), rainfall (B = -0.006, p = 0.0005), ferric luvisols (B = 0.539, p = 0.274), dystric nitosols (B = 0.133, p = 0.769) and pellic vertisols (B = 1.386, p = 0.008) soils types were the final variables in the model for predicting the probability of an area having an infection prevalence equivalent to or more than 50%. The two predictive risk maps suggest that urinary schistosomiasis is widely distributed and occurring in all the Local Government Areas (LGAs) in State. The high-risk areas (≥ 50% prevalence) however, are confined to scatter foci in the north western part of the State. The model also estimated that 98.99% of schools aged children (5–14 years) are living in areas suitable for urinary schistosomiasis transmission and are at risk of infection. Conclusion The risk maps developed will hopefully be useful to the state health officials, by providing them with detailed distribution of urinary schistosomiasis, help to delineate areas for intervention, assesses population at risk thereby helping in optimizing scarce resources.

An introduction is presented in which the editor discusses articles in the issue on topics including public health, veterinary and human parasites, and parasites of aquatic animals.

Utilization, efficacy, perception, and acceptability of rectal artesunates for treatment of malaria were assessed in 264 children below 5 years attending two tertiary health facilities in Abeokuta, Nigeria. The children systematically selected were 136 from State Hospital Ijaye and 128 from Federal Medical Centre (FMC), Idi-Aba. Body weights and vital statistics of the children were measured; and blood samples were collected before and 24 h after administration of the rectal artesunates (Plasmotrim-50/200 mg Artesunate) to evaluate the efficacy of the suppository. The first dose of rectal artesunate suppository was administered at a dose of 5-10 mg/kg of body weight per rectum. Giemsa thin and thick films were employed to determine parasite species, malaria parasite count/μL (MPC/μL), and percentage of parasitized red blood cells (PPRBCs). Data were analyzed using SPSS version 16.0. Plasmodium falciparum was the malaria parasite identified by blood examination, with a pretreatment prevalence of 98.9%. Male children had higher infection rate (55%) than females (45%), and infection among age groups and weight groups varied. Chi-square analysis revealed a significant difference between weight and malaria parasite count (p<0.05). Post-treatment analysis after 24 h showed that prevalence dropped by 73%, with females having higher crash rate (77%) than males (69%) but with no statistical difference (p>0.05) among the sexes. Chi-square analysis of pre- and post-treatment revealed a significant difference between MPC/μL and PPRBC at p<0.05. This confirmed the efficacy of rectal artesunate in reducing the parasite density (parasitaemia) within 24 h of treatment. On acceptability, 99.60% of parents accepted to use the suppository. However, 87.1% of parents preferred its usage, as it is easy to administer with no adverse effects when administered on their children. If health officials increase more public knowledge on the use of rectal artesunates, the high mortality now experienced in children under 5 years due to malaria disease would be greatly reduced.

Based on the hypothesis that consistent hyperglycemia can result in insulin resistance, we explored the induction of non-insulin dependent diabetes mellitus (NIDDM) using diet of high glycemic/low fat index and compared the effects on the physiology and histology of the rats. The rats were divided into 3 groups. DM was induced in the first group by single intraperitoneal injection of 150mg/kg alloxan monohydrate and in the second group by feeding the rats with diet of high glycemic index/low fat for 8 weeks. The pathophysiology and histopathology of DM were studied. Hyperglycemia was recorded in the alloxan and food-induced groups respectively. Both groups were also positive for glycosuria, which confirmed the induction of DM. Concentrations of plasma potassium, calcium, protein and urea were higher (p<0.05) in the alloxan-induced than the food-induced diabetic rats, whereas food-induced rats recorded higher hematological indices than the alloxan-induced group. Coronary risk indices were higher in food-induced diabetic rats than the alloxan-induced, while activities of antioxidant enzymes were significantly higher (p<0.05) in alloxan-induced diabetic rats than the food-induced rats. Marked degenerations of the Islets of Langerhans was observed in pancreas of alloxan-induced diabetic rats, whereas, histological examination of the pancreas of food-induced and control rats revealed no visible lesion. Liver and kidney of all food and alloxan-induced diabetic rats showed marked degeneration of the hepatocytes and the glomeruli respectively. This study presents a rat model of type II diabetes mellitus using food of high glycemic/low fat index with its consequent ionoregulatory disruptions, acute anemia, hyperlipidemia, nephropathy and hepatopathy.

The root and leaf extracts of four plants, Occimum gratissimum, Azadirachta indica, Pterocarpus santalinoides, and Pistia hyptis, were studied for repellent activities against the adults of Simulium damnosum sensu lato. The leaves and roots were extracted with 95% ethanol and the stocks were diluted with paraffin. The repellent activities of the extracts were investigated using human baits along the banks of River Oyan and River Ogun in southwestern Nigeria. The results showed that the root extract of O. grattissium and leaf extract of P. hyptis had highest repellent potentials with 78% and 78.1% protection against S. damnosum sensu lato, respectively, whereas the root and leaf of P. santalinoides recorded the least. Although there were significant differences in the percentage of protection of the extracts of the plants (p < 0.05), the variations in the percentage of protection of the leaf and root extracts were not statistically significant (p > 0.05). The study concludes that there exist some repellent efficacies in the extracts of the plants, most importantly O. grattissimum and P. hyptis. The plant extracts can further be developed in the prevention of man-vector contact in onchocerciasis endemic communities.