Mechanical transmission of pathogenic organisms: the role of cockroaches.

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 vulgaris, 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. cayetenensis and Isospora belli, cysts of Balantidium coli, ova of Ascaris lumbricoides, Anchylostoma deodunalae, Enterobius vermicularis, ova Trichuris trichura, larva of Strongyloides stercoralis. Cockroaches trapped in the toilets of houses with pit latrines had a mean bacterial and parasites count of 12.3 x 10(10) 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 x 10(7) org/ml and 31 parasites/ml respectively. A bacterial count of 78.9 x 10(7) 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 x 10(6) org/ml and 19 parasites/ml were recorded from kitchens of houses with water system. INTERPRETATION & CONCLUSION: Cockroaches represent an important reservoir for infectious pathogens, therefore, control of cockroaches will substantially minimise the spread of infectious diseases in our environment.

A comparative study on the susceptibility of male and female albino mice to Trypanosoma brucei brucei.

BACKGROUND & OBJECTIVES: Trypanosomiasis has remained a major set-back in the development of livestock farming in tropical Africa. Thus the need for ascertaining the trypanotolerant levels of domestic animal breeds and possible improvement on them cannot be over-emphasised. METHODS: Level of trypanotolerance in animals was compared between sexes using albino mice infected with a Nigerian strain of Trypanosoma brucei brucei at a 50% mouse lethal dose (MLD50). RESULTS: The male mice showed unrestrained parasite growth with a prepatent period (PP) of two days and a mean survival period (MSP) of six days corresponding to a gradual decrease in packed cell volume (PCV), body weight, diet response and white blood cells (WBC) count to the time of death. Their female counterparts showed a PP of three days and MSP often days with a similar PCV gradient but a refractory WBC count. There was no significant difference in the differential leucocytes count in both sexes. However, the eosinophils count was significantly higher in the infected animals. It was found that female albino mice exercised more parasite restraint than their male counterparts. INTERPRETATION & CONCLUSION: The result suggests that the female animals may be more trypanotolerant hence may be more useful in protein production in trypanosomiasis endemic areas. However, further research using large domestic breeds like goats and sheep may be required to confirm the hypothesis.