An investigation on and isolation of parasites that infect humans associated with Catha edulis leaves sold in selected parts of Nairobi County, Kenya

Abstract

Catha edulis (Khat) is a natural psycho-stimulant herb containing the alkaloid cathinone known for causing excitement, loss of appetite and euphoria among others, after chewing its young buds and tender leaves. Although khat is reported to cause various health problems, most of them have never been systematically investigated, especially on contamination with parasite stages and eventual transmission to humans. Food contamination may occur at any stage including preparation, production, processing and distribution. This risk therefore, depends largely on the health status of the handler, personal hygiene, knowledge and systematic application of food hygiene. This study explored the possibility of transmission of intestinal parasites through use of the herb. This survey was conducted between the months of December 2018 and May 2019 in Eastleigh, Kawangware, Kibra, Mathare and Dandora suburbs in Nairobi County. This involved 155 (105 males & 50 females) selected khat vendors using a structured questionnaire to collect demographic data. Khat leaves were collected in aerated bags, then processed and evaluated for presence of contaminant parasites that infect humans using concentration and direct methods, in the laboratory at Jomo Kenyatta University of Agriculture and technology. Data on environmental risk factors/conditions was gathered from the vendors through a structured questionnaire and physical observation of the surrounding. The minimum and maximum ages of respondents were 22 and 43 years respectively. Data obtained were analyzed using SPSS version 23.0 and significance pegged at <0.05. Parasites were isolated in 24 (15.4%) of the study sites: Giardia lamblia cysts were isolated in 10 sites (6.5%) and E. histolytica in 9 sites (5.8%) and were the main parasites across the suburbs. 54.8% (n=85) of the vendors stored the leaves on the ground uncovered. Garbage wastes were found in 70.3% (n=109) of the study sites. Presence of parasites was statistically associated with the area/ site, p=0.011 and the type of wastes (p=0.043). The present study revealed main contaminants of C. edulis leaves were cysts of G. lamblia (6.5%) and E. histolytica (5.8%); ova of A. lumbricoides (1.9%) and larvae of Strongyloides stercilaris (1.3%). Poor storage of leaves, personal hygiene and polluted environmental conditions significantly contributed to and represented potential routes for the transmission of parasitic infections. Public health education may be key to reducing parasites infections got through contaminations. Similarly, setting up of standard shops with required level of hygiene by the County Government for vending C. edulis leaves is essential.