Self reported symptoms and inhibition of acetylcholinesterase activity among Kenyan agricultural workers.

OBJECTIVES: This study was part of the East African pesticides project. The general objective was to assess health hazards posed by handling, storage, and use of pesticides, on agricultural estates and small farms with a view to developing strategies for prevention and control of pesticide poisoning. The aim of this paper is to describe the prevalence of symptoms in this population, to relate levels of inhibition to reported symptoms and evaluate at which levels of inhibition symptoms become increased. METHODS: Complete data were available for 256 exposed subjects and 152 controls from four regions in Kenya. A structured questionnaire on symptoms experienced at the time of interview was given to all subjects and controls. Information was also obtained on sex, age, main occupation, and level of education. Symptoms reported during the high exposure period, were initially clustered in broader symptom categories from reference literature on health effects of pesticides that inhibit cholinesterase (organophosphate and carbamate). Prevalence ratios were estimated for symptoms with changes in cholinesterase activity in serum. RESULTS: Symptom prevalence in exposed subjects was higher during the high exposure period than the low exposure period, although these differences were not significant. Interestingly, a clear and significant change in symptoms prevalence was found in the controls with a higher prevalence in the low exposure period. Analysis of the relation between cholinesterase inhibition and symptoms showed that prevalence ratios were significantly > 1 for respiratory, eye, and central nervous system symptoms for workers with > 30% inhibition. Similar results were found for analyses with the actual level of acetylcholinesterase activity. CONCLUSION: The results suggest the presence of a relation between exposure and acetylcholinesterase inhibition, acetylcholinesterase activity, and respiratory, eye, and central nervous system symptoms. Increased symptom prevalence was found at acetylcholinesterase activities generally considered to be non-adverse.

The status of pesticide usage in East Africa

A descriptive epidemiologic study using pretested questionnaires was conducted in East Africa in 1989/90 and looked at various types of pesticides in current usage in the region especially with regard to their procurement; distribution and utilization. Hospital records were examined for reported cases of pesticide poisoning as well as assessing the knowledge and the awareness of health care providers on the recognition and potential of pesticide poisoning. The main pesticide importers in the region were the Ministries of Agriculture whereas distribution was dominated by co-operative unions. Although pesticide regulatory mechanisms existed; their weak structures enabled the importation and usage of pesticides no longer in use in the countries of origin. Incidents of abuse were noted; as in the use of organochlorine pesticides on food crops and reported poisoning cases in the district hospitals where Kenya and Tanzania reported 455 and 736 cases respectively. Though tentative; more than 40 per cent of the health care professionals interviewed could not recognise pesticide poisoning cases. Therefore to avert pesticide related morbidity and mortality in the region; pesticide regulatory bodies need strenghning while pesticide users; the general public and health care workers should be educated on pesticides

Comparative aetiology of childhood diarrhoea in Kakamega and Kiambu Districts, Kenya.

Two hundred diarrhoea specimens collected during January to February 1988, from rural children aged 0 to 60 months in Kakamega District were examined for bacteria, parasites and rotavirus. The results were compared with a sample of 184 diarrhoea specimens matched for month of collection, taken from data collected in the same manner from children in Kiambu District. The mean ages of children in the 2 samples did not differ significantly. There were significant differences in the prevalence of specific potential pathogens isolated in the 2 areas. Notably, A. lumbricoides and rotavirus were more common in Kakamega, while G. lamblia, Entamoeba histolytica, Trichomonas hominis, Cryptosporidium sp., Hymenolepis nana and EPEC were more common in Kiambu. There was no difference with respect to prevalence of Campylobacter sp. or Blastocystis hominis. Factors which were probably important in determining aetiological differences included climate, water sources, animal contact and crowding. The differences highlight the fact that general predictions about aetiology cannot be made from isolated studies.

PIP: A total of 200 loose or watery specimens of diarrhea collected during January and February 1988 from rural children aged 0 to 60 months (mean age of 17.9 months) in Kakamega District, Kenya, were examined for bacteria, parasites, and rotavirus. The results were compared with data from a sample of 184 diarrhea specimens collected during January and February 1986, in the same manner from children with a mean age of 19.7 months in Kaimbu District. Complete investigations were accomplished in 140 of 184 specimens in the Kiambu sample. The most common organism in the Kakamega sample was A. lumbricoides (31%) compared with Escherichia coli (EPEC, 26.4%) and G. lamblia and (26.1%) in the Kiambu sample. There was no Cryptosporidium or Hymenolepis nana isolated in the Kakamega sample, while their frequencies were 2.7% and 3.8%, respectively, in the Kiambu sample. A. lumbricoides and rotavirus were significantly more common in the Kakamega sample, while all the protozoa, including G. lamblia, Entamoeba histolytica, and Trichomonas hominis, were more commonly isolated in the Kiambu ample. The Kiambu sample involved significantly more persistent diarrheas: more than 8 days (18.8%) than the Kakamega sample (3.5%) (p 0.001). A total of 44/140 (31.4%) of diarrheas were negative for potential pathogens in the Kiambu sample compared with 67/200 (33.5%) in the Kakamega sample. Mixed infections were common in both samples in which pathogens were isolated, with 53/133 (39.8%) in Kakamega being mixed, compared with 51/96 (53.1%) in Kiambu. One specimen in Kakamega had 5 potential pathogens (rotavirus, EPEC, C. lamblia, A. lumbricoides, B. hominis), while 1 specimen in Kiambu harbored 7 (EPEC, Shigella, Campylobacter, E. histolytica, T. hominis, G. lamblia, B. hominis). The community etiology of childhood diarrhea appears to be influenced by many factors which encourage direct fecal-oral transmission including climate, water sources, animal contact, and crowding.

Fluoride binding capacity of bone charcoal and its effects on selected micro-organisms.

Water is a major source of fluoride ions in areas where skeletal and dental fluorosis are endemic. We investigated the capacity of bone char to remove fluoride from water and its effects on selected bio-indicator organisms. Under static and dynamic conditions, the capacity of bone char was in the order of 2.5 mg of fluoride per g of bone char. Bone charcoal did not appear to support growth of yeast and S. aureus. E. coli and S. faecalis counts in the filtrate decreased with time but there was substantive growth in the bone charcoal.

Mixed infections in childhood diarrhoea: results of a community study in Kiambu District, Kenya.

One thousand four hundred and twenty diarrhoea specimens from 846 children aged 0 to 60 months were collected and analysed for bacteria, parasites and rotavirus over a 16 month period, from June 1985 to September 1986 inclusive. The study was conducted in 4 villages situated in Kiambu District, Kenya. All the specimens were analysed for rotavirus and parasites, including Cryptosporidium. The majority of the specimens were analysed for enteropathogenic Escherichia coli (EPEC), Shigella, Salmonella, Campylobacter and Aeromonas. Only 387 specimens were analysed for enterotoxigenic E. coli (ETEC). However, of this proportion analysed for ETEC, 33% were positive. A total of 344 specimens were negative for any organisms while a further 140 were only positive for parasites which have been implicated as being pathogenic, including Ascaris lumbricoides, Hymenolepis nana, Trichomonas hominis and Blastocysts hominis were considered to be at least potentially pathogenic and capable of causing diarrhoea. An average of only 29.4% of these organisms occurred as single isolates. The remaining infections were mixed, with a maximum of 7 potentially pathogenic organisms occurring together in a single specimen. The associations of certain organisms were significant, notably Campylobacter with Giardia lamblia. Campylobacter with EPEC, EPEC with Ascaris, and G. lamblia with rotavirus. The latter was a negative association.

Cryptosporidiosis and childhood diarrhoea in a rural community in Kenya.

Cryptosporidiosis has come to recent prominence as a cause of diarrhoea throughout the world in both adults and children, producing either an acute self-limiting diarrhoea or a protracted chronic diarrhoea which can be fatal in immunosuppressed patients. This study was therefore conducted to assess the prevalence of the infection among children less than five years of age in a rural community in Kiambu District, Kenya. 1420 diarrhoea specimens from children less than five years which were processed for bacteriology and parasitology were also examined for Cryptosporidium oocysts, using the modified Ziehl-Neelsen (ZN) acid-fast stain, 3.8% of all the diarrhoea samples were positive for oocysts. 320 non-diarrhoeic stools from children in the same age group were also examined and were all negative for Cryptosporidium oocysts. The results of this study would imply that infection with Cryptosporidium is associated with acute childhood diarrhoea in Kenya.