Evaluation of the toxicity of a mixture of dichlorvos and formaldehyde used for mosquito control in Nigeria

Vector control using insecticides (dichlorvos and formaldehyde) is an option in malaria control. This study evaluates the changes in haematological, biochemical, histo-pathological alteration and mutagenic potential induced by the insecticide mixture in albino rats for a period of 2-16 weeks. Haematological examination was done with the aid of an auto-analyser; biochemical assessment of alanine aminotransferase (ALT), aspartate aminotransferase (AST) and alkaline phosphatase (ALP), and other parameters was done using standard biochemical procedures. Mutagenicity was assessed, while histopathological examination was done with standard histological preparation. The red blood cell was significantly reduced (p<0.05) in the 12th and 16th week of exposure. There was significant decrease (p<0.05) in the ALT for the 12th and 16th week. Histopathological examination showed congestion, haemorrhage, bronchopneumonia and interstitial inflammation in the lungs, cytoplasmic inclusions in the liver while certain degree of degeneration in the kidney during the early period of exposure and normalcy was restored in the 12th and 16th week. Spermatozoa abnormalities significantly increased (p<0.05) with increase in duration of exposure. The haematological examination showed no significant reduction of the red blood cells in the 12th and 16th weeks, however, there was no serious impact on other blood parameters including kidney and liver. It was observed that the histopathological examination revealed severe impact on the lungs, mild damage to the liver and certain degree of degeneration in the kidney. The mutagenicity study suggests that the mixture may induce mutation. The adverse health implication of locally compounded or mixture of insecticides need to be addressed especially when considering their long term and continuous use in mosquito control.Keywords: malaria, insecticides, biochemical assessment, histopathology, mutagenicit

Knowledge, attitude and perception of malaria in Lagos State

Nigerian Quarterly Journal of Hospital Medicine Vol.10(1) 2000: 73-7

Public health implications of waste handling and consumption of food sourced from vendors in urban communities of Lagos, Nigeria

Waste handlers and food vendors were screened for parasitic infections. 297(152 waste handlers and 145 food vendors) specimen obtained from the participants were examined for parasitic infections using Kato-Katztechnique. Questionnaires which probed into their knowledge of cause, signs and symptoms, predisposing factors to infection and level of hygienic practices were administered. The results showed an overall prevalence ofparasitic infection of 25.7% for waste handlers and 61.4% for food vendors. There was no significant difference in the prevalence rates of parasitic  infections obtained for the two sexes among waste handlers (23.7% males,27.6% females; P > 0.05). Similarly, there was no gender difference  statistically among food vendors, though females had higher rates than the males (P > 0.05). Prevalence rates of  parasitic infections observed among waste handlers were 15.8%, 5.3% and 1.3% for Ascaris  lumbricoides, Hookworm and Trichuris trichiura respectively and; 28%, 27% and 6.2% respectively for food vendors showing higher levels of infections among the latter group. Light intensity of infection was obtained for each group, as shown by the mean geometric egg per gram per feaces (epg). The high prevalence of infection amongst food vendors as compared to the handlers can be attributed to poor sanitary conditions and poor knowledge on hygiene. There is therefore need for oversight by the food regulatory body to prevent the transmission among the food vendors and waste handlers.Key words: Soil Transmitted Helminthes, waste handlers, food vendors, Knowledge Attitude and Practices