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 speciescomposition, seasonal abundance, parity and feeding preference of indoor sampled mosquitoes inAbeokuta, south-western Nigeria.Methods: The mosquitoes were sampled weekly from five stratified locations using Center forDisease Control (CDC) light-traps between August 2005 and July 2006. The mosquitoes wereexamined for abdominal condition and dissected for age composition. Microscopic and precipitintechniques were also employed for the determination of host blood source.Results: A total of 2969 mosquitoes which belong to 10 species of mosquitoes were collectedduring the study period. Mansonia africana (35.65%) constituted the most abundant species followedby Culex quinquefasciatus (32.23%) and Anopheles gambiae complex (13.52%). Other species indecreasing 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 populationof mosquito vectors collected during the wet season as compared to the dry season and theirabundance was positively correlated with rainfall. The results showed that the majority of thevector species collected were unfed and nulliparous. Moreover, the blood meal test was positive forhuman blood.Conclusion: The preponderance of mosquitoes observed in the study is of public health concernsince they serve as vectors of most tropical diseases including malari

Fortieth Annual Conference Briefs

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Health knowledge and hygiene behaviors among schoolchildren in relation to Ascariasis in Ogun State, Nigeria.

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Cultivation and multiplication of viable axenic trypanosoma vivax in vitro and in vivo

Trypanosoma vivax was isolated from the blood of an infected laboratory mouse, washed and introduced into the prepared culture media, ME-99 and minimum essential medium (MEM), both containing laboratory prepared (commercial) horse serum and antibiotics (streptomycin and penicillin). The cultures were monitored in vitro for 12 days. There was an initial decline in parasitaemia in the first 48 h in both media, which later picked up to reach the peak of about 1.10 x 102 parasites/ml in ME-99 on day 5 and 6.2 x 10 parasites/ml in MEM on day 4. Thereafter, the parasites number tapered off to reach zero on day 9 in ME-99 and day 10 in MEM. No growth was recorded in the control, which contained normal saline (pH 7), horse serum and antibiotics. The result of the in vivo culture showed a different trend when compared to the in vitro. Multiplication was tremendous with a peak of about 3 x 10 parasites/ml of blood on day 22 (high inoculum) and day 24 (low inoculum) post infection. The slender trypomastigote parasites recovered in the in vitro culture was short and had a long, free flagellum and measured 23-25 um while that of the in vivo culture was long, slender, clongated, torpedo shaped body measuring between 30 and 32 um. During the course of the in vivo culture congenital transmission of trypanosomes was observed. The in vitro attenuated parasite conferred a degree of protection to 25% of the mice that were later infected with viable parasites indicating possible prophylactic effect of in vitro attenuated parasites. The study showed that T. vivax could not be cultured in large numbers on their own axenically in MEM and ME-99. However, ME-99 can be said to be more suitable compared to MEM for axenic cultivation of T. vivax as a result of the additional nutrients supplied by the tissue culture medium 199 present in medium ME-99. Also, the parasites multiplied better in vivo compared to the in vitro study, which could mean that the best means of culturing trypanosomes still remains the in vivo method

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

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

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 1.6% in Ewekoro, 2.3% in Odeda, 2.3% in Ado-odo/Otta, 3.8% in Ogun Waterside and 4.2% in 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

Occurrence and prevalence of nematodes in yam fields from four community-based farming scheme locations in Ogun State, Nigeria

Nematodes is one of the major biotic constraints affecting profitable yam production throughout Nigeria. They affect yams both in the field and in storage thus threatening food security and economic deprivation to growers and their households. The research work identified the types, frequency and population of nematodes associated with Dioscorea rotundata grown by the Farm Practical Year Programme Trainees of the Federal University of Agriculture, Abeokuta in four Community-based Farming Scheme locations, namely Isaga-Orile, Iwoye-Ketu, Ode-Lemo and Odogbolu in Ogun State. Soil samples were taken and assayed for nematode populations. Results showed that 26 Nematodes genera were found in the four locations ranging from 11 to 3201 individuals/250 g soil. Genera of plant-parasitic nematodes recovered included Scutellonema, Meloidogyne, Pratylenchus, Paratylenchulus, Trichodorus, Helicotylenchus, Hoplolaimus, Tylenchorhynchus, Aphelenchus, Xiphinema, Ditylenchus, Rotylenchulus, Rotylenchus and Aphelenchoides while the free-living nematode genera found included Aulolaimoides, Cephalobus, Cylindrocorpus, Lotonchus, Monhystera, Oncholaimus, Paraplectonema, Prismatolaimus, Dorylaimus, Tylencholaimellus, Tylencholaimus, and Tyleptus. Out of the twenty-six nematodes encountered, Meloidogyne spp. Scutellonema spp. and Pratylenchus spp. were mostly encountered in the soil and the only three recovered from the tubers which mean that these three nematodes are of economic importance to yam production. Farmers are therefore advised to go into yam production with management measure of nematodes putting the three key nematodes in mind, in order to avoid yield loss.Keywords: White guinea yam; Meloidogyne spp.; Scutellonema spp.; Pratylenchus spp

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 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