Sammy Olufemi Sam-Wobo

Urinary schistosomiasis among preschool children in a rural community near Abeokuta, Nigeria.

BackgroundThe 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.ResultsOf 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.ConclusionCommunity 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.

Helminthiasis and Hygiene Conditions of Schools in Ikenne, Ogun State, Nigeria

Background A study of the helminth infection status of primary-school children and the hygiene condition of schools in Ikenne Local Government Area of Ogun State, Nigeria was undertaken between November 2004 and February 2005 to help guide the development of a school-based health programme. Methods and Findings Three primary schools were randomly selected: two government-owned schools (one urban and the other rural) and one urban private school. No rural private schools existed to survey. A total of 257 schoolchildren aged 4–15 y, of whom 146 (56.8%) were boys and 111 (43.2%) were girls, took part in the survey. A child survey form, which included columns for name, age, sex, and class level, was used in concert with examination of stool samples for eggs of intestinal helminths. A school survey form was used to assess the conditions of water supply, condition of latrines, presence of soap for handwashing, and presence of garbage around the school compound. The demographic data showed that the number of schoolchildren gradually decreased as their ages increased in all three schools. The sex ratio was proportional in the urban school until primary level 3, after which the number of female pupils gradually decreased, whereas in the private school, sexes were proportionally distributed even in higher classes. The prevalence of helminth infection was 54.9% of schoolchildren in the urban government school, 63.5% in the rural government school, and 28.4% in the urban private school. Ascaris lumbricoides was the most prevalent species, followed by Trichuris trichiura, Taenia species, and hookworm in the three schools. Prevalence of infection in the government-owned schools was significantly higher than in the private school (χ 2 = 18.85, df = 2, p<0.0005). A survey of hygiene conditions in the three schools indicated that in the two government schools tapwater was unavailable, sanitation of latrines was poor, handwashing soap was unavailable, and garbage was present around school compounds. In the private school, in contrast, all hygiene indices were satisfactory. Conclusions These results indicate that burden of parasite infections and poor sanitary conditions are of greater public health importance in government-owned schools than in privately owned schools. School health programmes in government-owned schools, including deworming, health education, and improvement of hygiene conditions are recommended.

Biting behaviour of Simulium damnosum complex and Onchocerca volvulus infection along the Osun River, Southwest Nigeria

BackgroundStudies 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.ResultsThe 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.ConclusionThe 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.

Schistosoma haematobium infections in preschool children from two rural communities in Ijebu East, south-western Nigeria

There is an urgent need for information on schistosomiasis in preschool children, who are often excluded in mass treatment programmes. The prevalence and intensity of Schistosoma haematobium infection were determined in preschool children aged ≤ 6 years in two rural communities in Ijebu East, south-western Nigeria. Two urine samples each were collected from 83 preschool children from the two communities, tested for microhaematuria using reagent strips and then processed and examined with a microscope for S. haematobium eggs. Focus group discussions on perceptions of the disease and water contact practices were held in the communities with their guardians, caregivers and preschool children, using an interview guide. The prevalence of S. haematobium in the two communities was 14 (16.9%), with no significant differences (P = 0.661) in infection rate between boys (18.4%) and girls (14.7%). Both prevalence and intensity of infection did not increase significantly with age in both Korede and Obada community. However, there were significant differences in prevalence of infection between the two communities (P = 0.035). There was no association (P = 0.750) between intensity in boys (0.176 eggs/10 ml urine) and girls (0.110 eggs/10 ml urine). Focal group discussions with guardians and caregivers revealed that preschool children acquired infection early in their lives through exposure to infected stream water by their mothers, while the older children visit the stream for playing, bathing and swimming. It has therefore become imperative for preschool children to be included in the planning of schistosomiasis intervention programmes as a means of reducing transmission.

Rectal Artesunates, Their Utilization, and Parental Perception in the Management of Malaria in Children from Abeokuta, Southwestern Nigeria

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.

Comparative repellent activities of some plant extracts against Simulium damnosum complex.

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.

Molecular characterisation of the Simulium damnosum complex (Diptera: Simuliidae) found along the Osun River system, in south-western Nigeria.

Simulium damnosum s.l. are the only known vectors of Onchocerca volvulus in West Africa (Toè et al., 1997). At least nine sibling species of S. damnosum s.l. exist in this region and these siblings have varying vectorial capacities in the different ecozones (Wilson and Post, 1994). The savannadwelling group (S. damnosum s.s. and S. sirbanum) transmits the blinding, savanna strain of O. volvulus and the forest-dwelling group (S. squamosum and S. yahense) transmits the non-blinding, forest strain of the parasite (Tang et al., 1995). The members of the transition-zone-dwelling group (S. sanctipauli, S. leonense and S. soubrense) are commonly found in areas where the two strains of O. volvulus co-exist (Tang et al., 1995). Most of the classification of the S. damnosum s.l. in West Africa has been based on larval cytotaxonomy (Ibeh et al., 2006). The available cytotaxonomic techniques can only be applied to seventh-instar larvae and cannot be used to identify the adult flies that are involved in transmission. Adult S. damnosum s.l. have been investigated using iso-enzyme analysis (Thomson et al., 1990), morphotaxonomy (Garms and Zillman, 1984; Wilson et al., 1993), morphometrics (Garms et al., 1982; Wilson et al., 1993) and molecular techniques based on the amplification of the internal transcribed spacers (ITS) of the flies’ nuclear ribosomal DNA (Brockhouse et al., 1993). Unfortunately, each of these methods could only differentiate two or three of the sibling species, leaving the problem of adult identification unresolved. More recently, however, the amplification of the 16S ribosomal RNA and NADH dehydrogenase subunit 4 (ND4) mitochondrial genes has been found useful, and the electrophoretic migration of heteroduplex formations of these sequences has been used to distinguish at least six of the siblings that serve as the main vectors in the areas formerly covered by the Onchocerciasis Control Programme (OCP) in West Africa (Tang et al., 1995; Higazi et al., 2000). A heteroduplex assay has recently been employed to investigate the sibling composition of the biting adults of S. damnosum s.l. to be found along the Osun River, in south– western Nigeria. This river lies (at 8u209– 6u309N, 5u109–3u259E) in the forest zone of Nigeria, outside of the ‘OCP area’. Between February 2008 and January 2009, adult S. damnosum s.l. were collected every fortnight, as they landed on human volunteers at three catching points along the river (at Eleja, Ogbere and Budepo), and then morphologically classified into forest or savanna flies (Kurtak et al., 1981; Wilson et al., 1993). Fifty flies were randomly selected from the collections made during each of the three seasonal peaks (April–June, July–September and October–March; Mayr, 1969). The DNA in each selected fly was extracted using a commercial kit (DNeasyH blood and tissue kit; QIAGEN, Hilden, Germany) and then run in a PCR designed to amplify ND4 sequences (Tang et al., 1995). The denaturation and renaturation of the heteroduplex of the PCR products was carried out using S. damnosum s.s. as the heteroduplex driver. The heteroduplex Annals of Tropical Medicine & Parasitology, Vol. 104, No. 8, 679–683 (2010)