A simple, cost effective method for isolation and transportation of Leishmania parasites.

Isolation and propagation of Leishmania parasites using conventional culture methods are difficult, especially under field conditions. Transportation of live parasites requires the maintenance of low temperatures, which increases the cost considerably. The present study demonstrates that monophasic micro capillary culture is a simpler, more economical and better alternative to using conventional Evan's modified Tobie's medium to isolate and transport the Leishmania parasite over long distances without the use of temperature control methods.

Cutaneous leishmaniasis in southern Sri Lanka.

Cutaneous leishmaniasis is an established disease in Sri Lanka. The majority of cases have been reported from the North-Central Province, with the southern parts of the country considered less affected. However, during 2004, when the services of a dermatologist were available, a considerable number of patients were referred from the Southern Province, which formed the basis for this study. The clinical pattern, detailed geographical distribution within the Southern Province and periodicity of the cases were studied over a period of 12 months. Of the 113 patients diagnosed, the highest number was within the 10-19 years age group. Most patients were from densely populated rural areas around Matara, a large town within this province. There was a notable increase in the number of cases presenting during February-March and August-September, which are periods following monsoonal rains. Exposed areas of the skin were commonly affected, with the majority of patients having single lesions. Females and males were equally affected. This is in contrast to our previous findings in the North-Central Province where the majority of patients were male soldiers with multiple lesions.

Microculture for the isolation of Leishmania parasites from cutaneous lesions -- Sri Lankan experience.

Novy, McNeal and Nicolle (NNN) medium and Evans' modified Tobie's medium are two conventional media for the isolation of Leishmania parasites in in-vitro cultures. Both are biphasic, with a solid layer of blood agar, and are normally prepared in glass test-tubes. In Sri Lanka at least, a monophasic microcapillary culture, based solely on RPMI 1640 medium supplemented with foetal calf serum, has been found simpler, more economical and more sensitive, for the isolation of L. donovani from skin lesions, than the use of Evans' modified Tobie's medium.

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.

A simple device to maintain in vitro cultures of Leishmania in tropical countries.

A thermo-stable clay device to maintain in vitro Leishmania cultures in tropical countries within the optimal temperature range of 22 to 27 degrees C was developed. This being simple and economical could immensely benefit diagnosis and research on leishmaniasis in these countries.

Sri Lankan cutaneous leishmaniasis is caused by Leishmania donovani zymodeme MON-37.

Sri Lankan cutaneous leishmaniasis (CL), once considered sporadic, is fairly widespread in some parts of the country. Identification of 5 isolates from 4 CL patients by enzyme analysis during 2002 showed that they were all Leishmania donovani zymodeme MON-37, the parasite which also causes visceral leishmaniasis in India and East Africa.

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.

Third report of ocular parastrongyliasis (angiostrongyliasis) from Sri Lanka.

A further case of ocular parastrongyliasis has been seen in a patient from Sri Lanka. As it is a juvenile female worm it could not be identified to the species, but it is probably Parastrongylus (= Angiostrongylus) cantonensis which is the commonly reported species in the country. This is the third authentic case of such an infection in Sri Lanka in recent years.

A study of cutaneous myiasis in Sri Lanka.

BACKGROUND AND OBJECTIVES: Cutaneous myiasis (CM) due to Diptera fly larvae shows different patterns in different regions. Many modalities of treatment have been described. The objectives of our study were to identify the species causing CM in Sri Lanka, the common sites of infestation, and the contributory factors, and to assess some treatment modalities, in particular mineral turpentine and certain herbal preparations. METHODS: All patients with CM admitted or referred to the Dermatology Unit at the General Hospital, Kalutara, over 18 months starting from July 1997, and all patients with CM from the orthopedic and surgical wards of the National Hospital of Sri Lanka in Colombo over 6 months from July 1997, were studied. Details of the history and examination were recorded on specially designed forms. Maggots extracted were identified at the Department of Parasitology, Faculty of Medicine, University of Colombo. The modalities of treatment employed in the patients were recorded. In the Department of Parasitology, a colony of Chrysomya megacephala was maintained. Homogenized leaf extracts of Azadirachta indica (neem) and Pongamia pinnata (Indian beech) and mineral turpentine (active ingredient--low aromatic white spirits) were tested for efficacy in killing C. megacephala larvae in vitro. Leaf extracts were not used directly on patients. RESULTS: There were 16 patients (10 males and five females; the sex of one patient was not recorded). The mean age was 58.5 years (range, 11-94 years). Identification of larvae revealed C. bezziana in 14 (87.5%) and C. megacephala in two (12.5%) patients. The foot was affected in 15 (93. 7%) and the scalp in one patient. The immediate predisposing factor for CM in dermatology patients was infected dermatitis. The other relevant associated factors were: diabetes mellitus, psychiatric illness, leprosy, and mental subnormality. Turpentine was a useful adjunct in the removal of maggots manually. There were no side-effects to turpentine. In the in vitro testing, turpentine was 100% effective in killing maggots. Some patients required surgical removal under anesthesia. Indian beech and neem leaf extracts were not effective against Chrysomya larvae in vitro. CONCLUSIONS: All cases of CM were due to larvae of Chrysomya species. The commonest was C. bezziana. C. megacephala larvae causing CM have been reported for the first time in Sri Lanka. The foot was the site of predilection. Dermatitis, psychiatric illness, leprosy, diabetes, and mental subnormality were some contributory factors. Topically instilled mineral turpentine, followed by manual removal of maggots, was effective in most cases. The plant extracts tested in vitro were ineffective. As C. bezziana is an obligatory parasite capable of penetrating deeply, the importance of preventive measures is emphasized.

Recovery of a species of Brugia, probably B. ceylonensis, from the conjunctiva of a patient in Sri Lanka.

A species of Brugia, probably B. ceylonensis, was recovered from the conjunctiva of a patient in Sri Lanka for the first time. This infection represents only the second record of Brugia in the human conjunctiva, and is clearly zoonotic, acquired from a dog. Brugia ceylonensis has a distinct head bulb like that of Wuchereria bancrofti and B. malayi. However, the parasite recovered was not W. bancrofti, as specific IFAT and DNA probes gave negative results, and B. malayi is believed to have been eradicated from Sri Lanka several years ago. The presence of a distinct head bulb excludes the possibility that the parasite was B. buckleyi.

Locally acquired cutaneous leishmaniasis in Sri Lanka.

Cutaneous leishmaniasis in a Sri Lankan, who had not left the country, is reported. The diagnosis was confirmed by detecting the parasite in smears under microscopic examination. This is the first case report of locally acquired leishmaniasis in Sri Lanka.

Plasmodium vivax: isolation of mature asexual stages and gametocytes from infected human blood by colloidal silica (Percoll) gradient centrifugation.

The densities of human erythrocytes infected with P. vivax obtained from infected patients were determined by isopycnic centrifugation in continuous gradients of Percoll. The approximate densities of erythrocytes infected with rings were 1.086 to 1.1, trophozoites (amoeboid stages) 1.053 to 1.086, schizonts and gametocytes 1.053 to 1.056 and of the other cellular elements of blood, uninfected erythrocytes, 1.086 to 1.1, polymorphonuclear leucocytes 1.073 to 1.086 and mononuclear cells 1.062 to 1.073 g/ml. Based on these values, a one-step gradient of 47% Percoll was devised to separate erythrocytes infected with the more mature stages (trophozoites, schizonts and gametocytes) from uninfected erythrocytes. By this method it is possible to obtain parasitaemias of 88% to 98% from blood with starting parasitaemias of less than 0.7%. This method is therefore being routinely used for immunological, biochemical and molecular biological studies on P. vivax.