Study of dirofilariasis in a selected area in the Western Province.

INTRODUCTION: Human dirofilariasis is a zoonotic infection caused by the filarial worm, Dirofilaria (Nochtiella) repens, whose primary host is the dog. This infection is on the increase over the past decade in Sri Lanka and the prevalence of canine dirofilariasis in the country is also believed to be high. We present here a study on public awareness of dirofilariasis and the prevalence of this infection in dogs in Negombo, an urban area that has a high domestic canine population. OBJECTIVE: To assess the awareness of dirofilariasis infection among residents and study the prevalence of this infection in domestic dogs in Negombo. DESIGN: Prospective study. SETTING: Department of Parasitology, Faculty of Medicine, University of Colombo, Colombo 8, Sri Lanka. METHODS: A descriptive cross-sectional study within the city of Negombo during September and November 2003 using a pre-tested, interviewer-administered questionnaire with cluster sampling was done. Two hundred seventy adults, including 132 dog owners, were included in the study. Data analysis was done using the Epilnfo programme. The prevalence of canine dirofilariasis was studied in a group of 65 dogs over the age of 1 year. They were selected by cluster sampling with random choice of the streets within the study area. Stained thick blood films, made following an earlobe-prick at any time during the day, were microscopically examined for the presence of microfilariae. RESULTS: Forty nine of the respondents (18%) were aware of the existence of canine dirofilariasis while human dirofilariasis was known only to 6%. Awareness was related to the level of education. Knowledge of canine filariasis was better among pet owners (32/132) when compared to others (18/138; p < 0.05). Veterinary surgeons were acknowledged as the source of information by 38% of those who were aware of the disease. Forty five per cent (n = 29) of the dogs screened were positive for microfilariae. Out of these 18 and two dogs were infected with D repens. and B. ceylonensis, respectively, while nine others were co-infected with the two parasites. CONCLUSIONS: The knowledge of dirofilariasis is extremely poor in the study area. The high prevalence of filarial infections in dogs highlights the importance of improving the public awareness of this disease, especially among the dog owners. Proper management of this condition in dogs-the reservoirs of infection for human dirofilariasis, is important for the control of this zoonotic infection.

First successful in vitro culture of autochthonous Leishmania sp. in Sri Lanka.

Since the first autochthonous case of cutaneous leishmaniasis in Sri Lanka was reported in 1992 (1) attempts to culture the causative organisms have been unsuccessful. We report the first successful isolation of the local Leishmania sp. by in vitro culture, which would pave the way for species and strain indentification.

Megaselia scalaris (Diptera: Phoridae) can live on ripe bananas--a potential health hazard?

OBJECTIVE: Identification of larvae that inest bananas and investigating its habits. DESIGN: Laboratory based study. SETTING: Department of Parasitology, Faculty of Medicine, University of Colombo. METHODS: Bananas brought to the department with a query of maggot infestation were examined and the presence of maggots was confirmed. Maggots were allowed to develop into adults. The larvae and the flies were identified using standard keys. RESULTS: Megaselia scalaris was identified, the larvae of which infest ripe bananas. Three generations of M scalaris were reared using ripe bananas as the only source of food. Two other banana specimens yielded larvae that eventually grew into adult flies of Bactrocera species. CONCLUSIONS: In addition to Bactrocera spp. larvae of which are known pests in bananas, M scalaris larvae were detected as pests for the first time. We demonstrated that M scalaris can complete its life-cycle depending on ripe bananas as the only source of food. The vast consumption of bananas and the potential of M scalaris to cause intestinal and wound myiasis in humans make these findings medically important.