Evaluation of the therapeutic efficacy of praziquantel against schistosomes in seven countries with ongoing large-scale deworming programs.

The World Health Organization (WHO) recommends periodic assessment of the therapeutic efficacy of praziquantel (PZQ) to detect reduced efficacy that may arise from drug resistance in schistosomes. In this multi-country study (2014), we assessed the therapeutic efficacy of a single oral dose of PZQ (40 mg/kg) against Schistosoma mansoni (Brazil, Cameroon, Ethiopia, Mali, Madagascar and Tanzania), S. haematobium (Cameroon, Ethiopia, Mali, Tanzania and Zanzibar) and S. japonicum (the Philippines) infections in school-aged children, across a total of 12 different trials. Each trial was performed according to the standardized methodology for evaluating PZQ efficacy as described by the WHO. Overall, therapeutic efficacy, measured as the reduction in arithmetic mean of schistosome egg counts following drug administration (egg reduction rate; ERR), was high for all three schistosome species (S. mansoni: 93.4% (95%CI: 88.8-96.8); S. haematobium: 97.7% (95%CI: 96.5-98.7) and S. japonicum: 90.0% (95%CI: 68.4-99.3). At the trial level, therapeutic efficacy was satisfactory (point estimate ERR ≥90%) for all three Schistosoma species with the exception of S. mansoni in Cameroon where the ERR was 88.5% (95%CI: 79.0-95.1). Furthermore, we observed that in some trials individual drug response could vary significantly (wide 95%CI) and that few non-responsive individuals could significantly impact ERR point estimates. In conclusion, these results do not suggest any established reduced efficacy of the standard PZQ treatment to any of the three schistosome species within these countries. Nevertheless, the substantial degree of variation in individual responses to treatment in some countries underpins the need for future monitoring. The reported ERR values serve as reference values to compare with outcomes of future PZQ efficacy studies to ensure early detection of reduced efficacies that could occur as drug pressure continues increase. Finally, this study highlights that 95%CI should be considered in WHO guidelines to classify the therapeutic efficacy of PZQ.

Polyparasitism with Malaria and Intestinal Parasite Infections among Infants and Preschool-Aged Children in Egbedore, Osun State, Nigeria.

Polyparasitism is widespread in many communities in Sub-Saharan Africa. However, there is paucity of data on polyparasitism in infants and preschool-aged children (IPSAC), to inform policy developments. Therefore, a survey of 1110 consented IPSAC was undertaken in Egbedore Local Government Area (LGA), Osun State, Nigeria, to determine the prevalence of polyparasitism in IPSAC in ten randomly selected rural communities. Fresh stool and blood samples were collected and processed for intestinal parasites and malaria infection. Mothers/caregivers were interviewed using a structured questionnaire to obtain demographic data of their IPSAC and to document knowledge, attitude, and practice (KAP) on parasitic infections. Data obtained through the questionnaire were analyzed using EpiData version 3.1, while parasitological data were analyzed using Statistical Package for Social Sciences (version 20.0). Descriptive statistics were computed for demographic data and association which were tested using bivariate analysis at a 95% confidence level while significance was set at p < 0.05. The results showed that 349 (46.29%) were infected with a single parasite. Infants and preschool-aged children infected with double, triple, and quadruple parasites are 268 (35.54%), 122 (16.18%), and 15 (1.99%), respectively. The prevalence of polyparasitism is 405 (53.71%). Although females (54.07%) were more infected than males (45.93%), there was no significant difference (p > 0.05) observed. Significantly (p < 0.05) more preschool children (65.93%) harbour more infections than the infants do (34.07%). Ara community (14.81%) had the highest cases of polyparasitized IPSAC, but no significant difference (p > 0.05) was observed across the communities. Double parasitic infection of Plasmodium falciparum and Ascaris lumbricoides (30.12%) and triple parasitic infection of P. falciparum, A. lumbricoides, and T. trichiura (14.81%) were the most common forms of polyparasitism encountered in the study. This study showed that polyparasitism is a burden in IPSAC and needs further investigation.

Epidemiological evaluation of onchocerciasis along Ogun River System, southwest Nigeria.

BACKGROUND & OBJECTIVE: Epidemiological studies were carried out to assess the prevalence and community microfilarial load (CMFL) of onchocerciasis after repeated annual treatment with ivermectin along Ogun river System, southwest Nigeria. METHOD: Skin snips were taken from consented participants in 11 selected communities along the River system. The microfilarial load of the community was estimated. RESULTS: The prevalence and CMFL varied significantly in the communities (p <0.05). The prevalence of onchocerciasis ranged from 19.1 to 45.6%, while the CMFL ranged from 0.11 to 1.03 microfilariae per skin snip. The CMFL recorded was <5 microfilariae per skin snip, i.e. recognized by WHO as threshold value in certifying the communities to be free of onchocerciasis as public health problem, thus, signifying the possibility of onchocerciasis elimination in the study area. CONCLUSION: Efforts should therefore be intensified to achieve improved ivermectin coverage and compliance in annual ivermectin treatment in order to completely eliminate onchocerciasis as a public health problem in the studied communities.

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.

Population dynamics of indoor sampled mosquitoes and their implication in disease transmission in Abeokuta, south-western Nigeria.

BACKGROUND & OBJECTIVES: A longitudinal study was carried out to investigate the species composition, seasonal abundance, parity and feeding preference of indoor sampled mosquitoes in Abeokuta, south-western Nigeria. METHODS: The mosquitoes were sampled weekly from five stratified locations using Center for Disease Control (CDC) light-traps between August 2005 and July 2006. The mosquitoes were examined for abdominal condition and dissected for age composition. Microscopic and precipitin techniques were also employed for the determination of host blood source. RESULTS: A total of 2969 mosquitoes which belong to 10 species of mosquitoes were collected during the study period. Mansonia africana (35.65%) constituted the most abundant species followed by Culex quinquefasciatus (32.23%) and Anopheles gambiae complex (13.52%). Other species in decreasing order of abundance were Coquilletidia maculipennis (8.2%), Aedes albopictus (5.9%), Ae. aegypti (1.93%), M. uniformis (1.81%), Cx. duttoni (0.25%), Cx. tigripes (0.25%) and An. funestus (0.25%). Seasonal abundance revealed a significant difference (p <0.05) in the population of mosquito vectors collected during the wet season as compared to the dry season and their abundance was positively correlated with rainfall. The results showed that the majority of the vector species collected were unfed and nulliparous. Moreover, the blood meal test was positive for human blood. CONCLUSION: The preponderance of mosquitoes observed in the study is of public health concern since they serve as vectors of most tropical diseases including malaria.

Mosquito larval habitats and public health implications in Abeokuta, Ogun State, Nigeria.

The larval habitats of mosquitoes were investigated in Abeokuta, Nigeria in order to determine the breeding sites of the existing mosquito fauna and its possible public health implications on the residents of the City. The habitats were sampled between August 2005 and July 2006 using plastic dippers and a pipette. The habitats were grouped as ground pools/ponds, gutters/open drains, tyres, domestic containers and treeholes/ leaf axils. Ten species of mosquitoes were encountered in the five habitats namely Mansonia africana, M. uniformis, Culex quinquefasciatus, Aedes aegypti, Ae. albopictus, Ae. vittatus, Cx tigripes, Anopheles gambiae s.l., An. funestus and Eretmapodite clnysogaster. Ae. aegypti bred in all the habitats sampled while Cx quinquefasciatus bred in four habitats except tree holes/leaf axils. An. gambiae s.l and Ae. albopictus occurred in three habitats while other species bred only in one or two habitats. Ground pools and domestic containers recorded the highest number of species followed by gutters/open drains. Tree holes/leaf axils was the least preferred habitat with the lowest number of species occurrence. However, statistical analysis revealed non-significant difference in species occurrence in the five habitats. The availability of the habitats to support the breeding of Aedes, Culex and Anopheles, which are known vectors of urban yellow fever, lymphatic filariasis and malaria suggest that the residents ofAbeokuta City are at risk of mosquito-borne diseases. It is important that residents of the City are enlighten on the environmental factors that contribute to mosquito breeding and that the Government should institute proper sanitation measures to reduce mosquito breeding sites.

Knowledge and practices on malaria treatment measures among pregnant women in Abeokuta, Nigeria.

The knowledge and practices on malaria treatment measures were assessed among 1400 pregnant women in semi-urban and rural communities (Akomoje, Iberekodo, Osiele and Sabopapamaru) of Abeokuta, Nigeria in 2006. Data was collected using structured questionnaires and focus group discussions. The largest proportion (41%) of the respondents was in the age group 21-25years. About three quarters (74%) of the women were multigravids. Sixty-five percent of the women had between three to four episodes of malaria per year. According to the respondents, symptoms associated with malaria in pregnancy included abdominal pains and foetal weakness due to reduced kicks (53%), body pains and headaches (27%) and anaemia (20%). Sixty-eight percent of the pregnant women utilized herbs for treating symptoms associated with malaria due to its effectiveness and suitability and not due to financial constraint or lack of access to health facility. Though most women utilized herbs, 32% relied more on the use of antimalarials. Sulfadoxine-pyrimethamine was the preferred antimalarial during pregnancy at the 2nd and 3rd trimesters. Only 15% of the women were using insecticide treated mosquito nets for personal protection. The majority (77%) of respondents used nylon net to screen their windows off mosquitoes. Since malaria poses adverse effect on the mother and developing foetus, health education becomes very essential to the traditional birth attendants and the women who patronize them. Pregnant women who attend traditional birth homes should be encouraged to also attend orthodox antenatal clinics, in order to receive proper and adequate treatment against malaria for themselves and the foetus.

Mosquito larval habitats and public health implications in Abeokuta, Ogun State, Nigeria

Abstract: The larval habitats of mosquitoes were investigated in Abeokuta, Nigeria in order to determine the breeding sites of the existing mosquito fauna and its possible public health implications on the residents of the City. The habitats were sampled between August 2005 and July 2006 using plastic dippers and a pipette. The habitats were grouped as ground pools/ponds, gutters/open drains, tyres, domestic containers and treeholes/ leaf axils. Ten species of mosquitoes were encountered in the fi ve habitats namely Mansonia africana, M. uniformis, Culex quinquefasciatus, Aedes aegypti, Ae. albopictus, Ae. vittatus, Cx tigripes, Anopheles gambiae s.l., An. funestus and Eretmapodite clnysogaster. Ae. aegypti bred in all the habitats sampled while Cx quinquefasciatus bred in four habitats except tree holes/leaf axils. An. gambiae s.l and Ae. albopictus occurred in three habitats while other species bred only in one or two habitats. Ground pools and domestic containers recorded the highest number of species followed by gutters/open drains. Tree holes/leaf axils was the least preferred habitat with the lowest number of species occurrence. However, statistical analysis revealed non-signifi-cant difference in species occurrence in the fi ve habitats. The availability of the habitats to support the breeding of Aedes, Culex and Anopheles, which are known vectors of urban yellow fever, lymphatic fi lariasis and malaria suggest that the residents of Abeokuta City are at risk of mosquito-borne diseases. It is important that residents of the City are enlighten on the environmental factors that contribute to mosquito breeding and that the Government should institute proper sanitation measures to reduce mosquito breeding sites

MONRATE: A descriptive tool for calculation and prediction of re-infection of Ascaris lumbricoides (Ascaridida: Ascarididae)

The study presents an interactive descriptive tool (MONRATE) for calculating and predicting reinfection rates and time of Ascaris lumbricoides following mass chemotherapy. The implementation was based on the theoretical equation published by Hayashi in 1977, for time-prevalence: Y=G [1-(1-X)N-R] as modified by Jong-Yil in 1983. Using the Psuedo-Code of the MONRATE tool, the calculated monthly reinfection rates (X) for the LGAs are (names are locations in Nigeria in a region predominately populated by the Yoruba speaking tribes of Nigeria whose traditional occupations are agriculture and commerce): Ewekoro (1.6 %), Odeda (2.3 %), Ado-odo/Otta (2.3 %), Ogun Waterside (3.8 %) and Obafemi/Owode (4.2 %). The mathematical mean of ‘X’ values in the study areas for Ogun State was 2.84. The calculated reinfection time (N months) for the LGAs are varied such as Ado-odo/Otta (12.7), Ogun Waterside (21.8), Obafemi/Owode (22.92), Odeda (25.45), and Ewekoro (25.9). The mean value for N in Ogun State was 21.75. The results obtained from MONRATE were compared with those obtained using the mathematical equation and found to be the same. Rev. Biol. Trop. 55 (3-4): 755-760. Epub 2007 December, 28.

Se presenta una herramienta descriptiva e interactiva (MONRATE) para calcular y predecir las tasas y tiempo de reinfección con Ascaris lumbricoides tras un tratamiento de quimioterapia. Nos basamos en la ecuación propuesta por Hayashi en 1977 para el tiempo de prevalencia: Y=G [1- (1-X)N-R], según la modificó Jong-Yil en 1983. Utilizando el código Psuedo de la herramienta de MONRATE, las tasas de reinfección mensuales (X) para varios sitios de Nigeria, África, son: Ewekoro (1.6 %), Odeda (2.3 %), Ado-odo/Otta (2.3 %), Ogun Waterside (3.8 %) y Obafemi/ Owode (4.2 %). El promedio matemático de los valores de "X" en el área de estudio del Estado de Ogun fue 2.84. El tiempo de reinfección calculado (N meses) para LGAs es variado: Ado-odo/Otta (12.7), Ogun Waterside (21.8), Obafemi/Owode (22.92), Odeda (25.45) y Ewekoro (25.9). El valor promedio para N en el Estado de Ogun fue 21.75. Los resultados del programa MONRATE son iguales a los producidos por la ecuación.

MONRATE: A descriptive tool for calculation and prediction of re-infection of Ascaris lumbricoides (Ascaridida: Ascarididae).

The study presents an interactive descriptive tool (MONRATE) for calculating and predicting reinfection rates and time of Ascaris lumbricoides following mass chemotherapy. The implementation was based on the theoretical equation published by Hayashi in 1977, for time-prevalence: Y=G [1-(1-X)(N-R)] as modified by Jong-Yil in 1983. Using the Psuedo-Code of the MONRATE tool, the calculated monthly reinfection rates (X) for the LGAs are (names are locations in Nigeria in a region predominately populated by the Yoruba speaking tribes of Nigeria whose traditional occupations are agriculture and commerce): Ewekoro (1.6%), Odeda (2.3%), Ado-odo/Otta (2.3%), Ogun Waterside (3.8%) and Obafemi/Owode (4.2%). The mathematical mean of 'X' values in the study areas for Ogun State was 2.84. The calculated reinfection time (N months) for the LGAs are varied such as Ado-odo/Otta (12.7), Ogun Waterside (21.8), Obafemi/Owode (22.92), Odeda (25.45), and Ewekoro (25.9). The mean value for N in Ogun State was 21.75. The results obtained from MONRATE were compared with those obtained using the mathematical equation and found to be the same.

MONRATE; a descriptive tool for calculation and prediction of re-infection of Ascaris lumbricoides

The objective of the study was to develop an interactive and systematic descriptive tool; MONRATE for calculating and predicting reinfection rates and time of Ascaris lumbricoides following mass chemotherapy using levamisole. Each pupil previously treated was retreated 6 or 7 months after the initial treatment in Ogun State; Nigeria. The implementation was based on the theoretical equation for time-prevalence: Y = G [1 -(1-X)N-R]. Using the Psuedo- Code of the MONRATE tool; the calculated monthly reinfection rates (X) for the LGAs were 1.6in Ewekoro; 2.3in Odeda; 2.3in Ado-odo/Otta; 3.8in Ogun Waterside and 4.2in Obafemi/Owode. The mathematical mean of 'X' values in the study areas for Ogun State was 2.84. The calculated reinfection time (N months) for the LGAs varied such as Ado-odo/Otta (12.7); Ogun Waterside (21.8); Obafemi/Owode (22.92); Odeda (25.45); and Ewekoro (25.9). The mean value for N in Ogun State was 21.75. The results obtained from MONRATE were compared with those obtained using the mathematical equation and were found to be the same but MONRATE was faster in computation and more accurate. It is concluded that MONRATE is a veritable tool that can be used in the execution of control programme involving mass treatment against A. lumbricoides

Gastrointestinal helminth parasites of the black rat (Rattus rattus) in Abeokuta, southwest Nigeria.

A survey of 612 black rats, Rattus rattus (282 mates and 330 females), for infections with helminth parasites was carried out in Abeokuta, in southwest Nigeria. Three hundred and ninety six (64.7%) were infected with one or more of seven species of helminths comprising three cestodes (Hymenolepis diminuta, Taenia taeniaeformis (cyst) and Raillietina sp.) three nematodes (Mastophorus muris, Trichuris muris and Syphacia sp.) and one acanthocephalan (Moniliformis moniliformis). Although the prevalence of infection in males (76.6%) was more than in females (54.5%) (P<0.01), there was no difference in the mean intensity of infection, MI, (males=11.6+/-0.94, females=11.1+/-1.56). Among the different weight classes, rats of 100-130 g were more infected (893%) and had the highest mean intensity (MI=21.6) than those that weighed <100 g (47.1%, MI=6.4) and >130 g (73.9%, MI=9.3). Moniliformis moniliformis was the most common species encountered (39.2%) and had the highest mean intensity in both sexes (x=7.4+/-0.74). Considering the rat-man proximity, this finding has considerable public health implications.