J Vect Borne Dis 42, December 2005 pp. 129���134 Mechanical transmission of pathogenic organisms: the role of cockroaches Y.M. Tatfenga, M.U. Usuanleleb, A. Orukpeb, A.K. Digbana, M. Okoduac, F. Oviasogied & A.A. Turayc aLahor Public Health and Research Centre, Benin City bDepartment of Zoology, Ambrose Alli University, Ekpoma cDepartment of Medical Laboratory Sciences, College of Medicine, Ambrose Alli University, Ekpoma dDepartment of Mi- crobiology, University of Benin, Benin City, Edo State, Nigeria Background & objectives: Cockroaches (Diploptera punctata) are basically tropical insects and will do their best to find a home that is both warm and moist. Their involvement in the transmission of tropical diseases is poorly investigated in Africa. Methods: A study on the bacterial, fungal and parasitic profile of cockroaches trapped in and around houses in Ekpoma was carried out using standard microbiological techniques. Results: Of a total of 234 cockroaches trapped from different sites (toilets, parlours, kitchens and bedrooms) in houses with pit latrines and water system, the bacterial, fungal and parasitic isolates were identical irrespective of the site, these included: E. coli, Klebsiella pneumoniae, Proteus vul- garis, Proteus mirabilis, Citrobacter freundii, Enterobacter cloacae, Salmonella sp, Pseudomonas aeruginosa, Serretia marcescens, S. aureus, S. feacalis, S. epidermidis, Aeromonas sp, Candida sp, Rhizopus sp, Aspergillus sp, Mucor sp, cysts of E. hystolitica, oocysts of C. parvum, C. cayetenen- sis and Isospora belli, cysts of Balantidium coli, ova of Ascaris lumbricoides, Anchylostoma deodu- nalae, Enterobius vermicularis, ova Trichuris trichura, larva of Strongyloides stercoralis. Cock- roaches trapped in the toilets of houses with pit latrines had a mean bacterial and parasites count of 12.3 �� 1010 org/ml and 98 parasites/ml respectively, while those trapped in the houses with water system had a mean bacterial and parasitic count of 89.5 �� 107 org/ml and 31 parasites/ml respectively. A bacterial count of 78.9 �� 107 org/ml was recorded from cockroaches trapped from the kitchens of houses with pit latrines. On the other hand a mean bacterial and parasitic count of 23.7 �� 106 org/ml and 19 parasites/ml were recorded from kitchens of houses with water system. Interpretation & conclusion: Cockroaches represent an important reservoir for infectious patho- gens, therefore, control of cockroaches will substantially minimise the spread of infectious diseases in our environment. Key words Cockroaches ��� infestation ��� Nigeria ��� parasite count ��� pathogens A great variety of insects are carrier of pathogens1,2. Cockroaches (Diploptera punctata) are known to carry a diverse pathogenic bacteria flora, different protozoans, pathogenic worms, fungus and viruses3,4, but their role in the direct transmission of infection has seldom been established5. Cockroaches have survived on the earth for more than 300 million years virtually without change. They are survivors, and will likely be with us for a few more million years. Cockroaches are basically tropical in- sects and will do their best to find a home that is both warm and moist. They are especially attracted to wet Research Articles

J VECT BORNE DIS 42, DECEMBER 2005 130 areas and will be found in abundance near leaking fau- cets or pipes, wet sponges, persistently damp corners, areas where there is frequently standing water, or areas where continual moisture is usually available, such as drains, kitchens, bathrooms and maintenance rooms with sink traps. Water and steam pipes frequently serve as migration routes from room-to- room6. The filthy breeding habits, feeding mechanisms and in- discriminate travel between filth and food make some groups of synanthropic insects such as nonbiting flies and cockroaches efficient vectors of human enteric protozoan parasites. Twenty-one species of filth flies have been listed by regulatory agencies concerned with sanitation and public health as causative agents of gastrointestinal diseases based on synanthropy, endo- phily, communicative behaviour and strong attraction to filth and human food. Outbreaks and cases of food- borne diarrhoeal diseases in urban and rural areas are closely related to the seasonal increase in abundance of filth flies, and enforced fly control is closely related to reductions in the occurrence of such diseases6. Material & Methods Study area: This study was carried out in Ekpoma between January and June 2005. Ekpoma is a rural settlement hosting a tertiary institution growing to be a semi-cosmopolitan town. It is mostly populated by the Esan people of Edo State and students from various parts of Nigeria. Sanitary conditions in this village are almost underdeveloped. Faecal disposal and water supply are very elementary, the majority of the popu- lation relies on pit toilets for faecal disposal and hand- dug wells for water storage. These facilities could contribute immensely to the proliferation of insects such as mosquitoes, cockroaches, etc. which are re- ported to be serious vectors of parasitic, bacterial, vi- ral and fungal diseases. Sample collection/size: Two hundred and fifty-two (252) adult cockroaches were trapped from different parts of the houses in Ekpoma for both parasitological and bacteriological studies. The cockroaches des- tined for bacterial and fungal studies were collected into sterile universal containers, while those for para- sitic studies were collected into universal containers containing 5 ml of formol saline. The insects were transported to the laboratory immediately for analysis. Parasitological studies: Each universal containing a cockroach in formol saline was shaken vigourously to detach the parasites from the insect body. The fluid was transferred to a conical test tube and spun at 3000 rpm for 5 min. The deposit was transferred onto a clean glass slide, covered with a cover slip and viewed with �� 40 microscope objective lens. The par- asites were identified and counted. Kinyoun stain: The deposits of the spun fluid were stained using modified Ziehl Nelseen stained as indi- cated by Cheesbrough7 for characteristic features of Cryptosporidium parvum and Cyclospora cayeten- ensis. Bacteriological and fungal studies: To each sterile universal container with a cockroach, 5 ml of sterile normal saline was added and shaken vigourously, a loopful of each suspension was cultured on Mac Con- key agar, blood agar, deoxycholate citrate (DCA) and Sabouraud dextrose agar plates. The plates were in- cubated at 37oC for 24 h. The organisms were identified using standard bacteri- ological techniques as described by Mackie and Mc Cartney8. Total viable count: A ten-fold dilution was carried out on each suspension to determine the total viable count of each cockroach using the pour plate method counts were made on plates showing discrete and evenly distributed colonies. Results This study revealed that cockroaches trapped from different sites (toilets, parlours, kitchens and bed- rooms) in the houses with pit latrines and water sys-