(Diptera: Psychodidae) species in Sri Lanka - Semantic Scholar

Vol. 36, Supplement 1

Journal of Vector Ecology

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Distribution and ecological aspects of sand fly (Diptera: Psychodidae) species in Sri Lanka Yusuf Ozbel1*, Chizu Sanjoba2, Bulent Alten3, Masahito Asada2, Jerome Depaquit4, Yasunobu Matsumoto2, Samiye Demir5, R.R.M.L.R. Siyambalagoda6, R.P.V. J. Rajapakse7, and Yoshitsugu Matsumoto2 1 Ege University Medical School Department of Parasitology, Bornova, Izmir, Turkey Department of Molecular Immunology, School of Agricultural and Life Sciences, University of Tokyo, Tokyo, Japan 3 Hacettepe University Science Faculty, Department of Ecology, Beytepe, Ankara, Turkey 4 University of Reims Faculté de Pharmacie, Laboratoire de Parasitologie, 51 rue Cognacq Jay 51096 Reims Cedex, France 5 Ege University Science Faculty, Department of Zoology, Bornova, Izmir, Turkey 6 Anti-Malaria Campaign, Department of Health, Colombo, Sri Lanka 7 Department of Veterinary Pathobiology, Faculty of Veterinary Medicine and Animal Science, University of Peradeniya, Sri Lanka 2

ABSTRACT: Human indigenous cutaneous leishmaniasis caused by Leishmania donovani complex is endemic in Sri Lanka. We performed an entomological survey to determine the distribution of probable vector species. Sand flies were collected in districts in the dry zone, in the wet zone highlands, and in the wet zone coastal belt of Sri Lanka using CDC light traps, sticky traps and cattle-baited net traps during July, 2005. The survey was reconducted in February, 2006. Overall, 584 sand flies belonging to Phlebotomus (266 specimens, 2 species) and Sergentomyia (318 specimens, 8 species) genera were collected. A total of 266 Phlebotomus was identified as P. argentipes (258/266; 97%) and P. stantoni (8/266; 3%). The identification studies of Sergentomyia specimens showed that there are at least 8 species in Sri Lanka. Higher number of Phlebotomus sand flies (76/266) were caught in the southern part of the country compared to the other parts probably due to different ecological aspects. P. argentipes were widely distributed throughout the island whereas P. stantoni were collected only in four districts. Since P. argentipes is known to be the vector of L. donovani responsible of visceral leishmaniasis in India, this species may be incriminated as the most possible vector of human cutaneous leishmaniasis in Sri Lanka. Journal of Vector Ecology 36 (Supplement 1): S77-S86. 2011. Keyword Index: Cutaneous leishmaniasis, , sand fly, Sri Lanka.

INTRODUCTION Sri Lanka was considered as free from leishmaniasis until 1990, with the exception of cases of workers returning from the Middle East and Africa (Naotunne et al. 1990). Subsequently, the first autochthonous cutaneous leishmaniasis case was reported in 1992 (Athukorale et al. 1992) and since 2001, over 2,000 cases were referred to the University of Colombo from almost all districts of the country (Karunaweera and Rajapaksa 2009) and parasites were isolated from a few patients and Leishmania donovani zymodeme MON-37 was identified as the causative organism of cutaneous leishmaniasis (Karunaweera et al. 2003) in this country. DNA sequencing and microsatellite analyses showed that these parasites were closely related to those causing visceral leishmaniasis in the Indian subcontinent (Siriwardana et al. 2007), Kenya (Kuhls et al. 2007) and Cyprus (Antoniou et al. 2008). In addition to CL, the first reported autochthonous visceral case was a 36 year- old woman from North Central Province who had no history of overseas travel (Abeygunasekara et al. 2007). Cutaneous leishmaniasis became a health problem in Sri Lanka and was included in the list of notifiable diseases in

Sri Lanka in October, 2008. Hospital records also indicated two other autochthonous visceral cases during the period of 2007 to 2008, and a patient with extensive mucosal tissue destruction could be considered as a further proof for the potential of the prevalent species to invade tissues or visceralize and result in a much more severe form of disease. It is reported that the “Action Plan” was recently developed by the health authorities and academics in Sri Lanka (Karunaweera 2009). There is now evidence of an emerging epidemic of CL in the southern part of the island. A total of 534 CL cases was reported between 2006 - July, 2008, mainly from Devinuwara, Dickwella, Tangalle and Beliatta towns (Matara and Hambantato districts) located in southern Sri Lanka (Rathayanake et al. 2009). The case records indicate a wide age range being affected (range: 1-92 years), with the age group of 21-40 years being the most frequently affected (Karunaweera 2009). Leishmaniases are transmitted by several different species of sand flies. Although the first study on Ceylonese sand flies was published in 1938 by Theodor, still little is known about the sand fly fauna and distribution of species throughout the country (Karunaweera 2009). Information

Journal of Vector Ecology March 2011

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about possible vector species of CL in Sri Lanka is very limited and only two species of Phlebotomus are known to exist in the country (Rajapaksa et al. 2007). The few studies pointed out the wide distribution of Phlebotomus argentipes throughout the island. This species is the vector of L. donovani, the agent of VL (kala-azar) in India. The only other sand fly of potential vector status recorded locally is P. stantoni, a jungle species feeding on wild rodents (Athukorale et al. 1992, Naotunne et al. 1990). The studies carried out so far also support the anthropophagic behavior and vectorial competence of the local vector, P. argentipes (Lane et al. 1990, Surendran et al. 2005). The climate of Sri Lanka is tropical and moderated by ocean winds and considerable moisture. Most temperature variation in the country is determined by elevation rather than season, with cooler temperatures at higher elevations. Most of the east, southeast, and northern parts of the country comprise the “dry zone”, which receives between 1,200 mm and 1,900 mm of rain annually. Much of the rain in these areas falls from October to January; during the rest of the year there is very little precipitation. The arid northwest and southeast coasts receive the least amount of rain at 600mm to 1,200 mm per year. The mountains and the southwestern part of the country, known as the “wet zone”, receive ample rainfall with an average of 2,500 mm. From an agro-ecological point of view, which represents a particular combination of the natural characteristics of climate, soil and relief, an “intermediate zone” is described, running between the dry and wet zones and receiving a mean annual rainfall between 1,750 to 2,500 mm with a short and less prominent dry season. As low temperature is an important climatic factor affecting plant growth in the wet and intermediate zones of Sri Lanka, a sub-division based on the altitude takes into account the temperature limitations in these two climatic regions. In this delineation, the low country is demarcated as the land below 300 m in elevation and the mid country with elevation between 300 and 900 m, while the up country is the land above 900 m elevation. On the Indian subcontinent, as well as in Sri Lanka, there are no entomological studies to elucidate vector behavioral habits, feeding preferences or insecticide susceptibility patterns, although they are the important aspects for disease control. As a first step, the sand fly species and their distribution in the endemic region or country have to be known. In the present study, we attempted to understand the sand fly fauna according to different climatic zones affecting ecological situation in Sri Lanka. MATERIALS AND METHODS Study areas The field study was performed throughout the island from north to the south. The areas where endemic and non-endemic for cutaneous leishmaniasis were chosen as sampling site locations (Table 1). The sand fly collection localities were divided into three sections according to the geographical zones and climatic features. The first area

(from 1 to 6 in Table 1) was located in dry zone and lowland plains in the northeast and northwest part of the country. Much of the rain in these area falls from October to January; during the rest of the year there is very little precipitation but not actually dry (Figure 1A). The second area (from 7 to 10 in Table 1) was located in the wet zone and highlands in the central part of the country (Figure 1B). The third area (from 11 to 13 in Table 1) was located in the wet zone and coastal belt in the southern part of the country (Figure 1C). Many physical characteristics of the houses and environment are related to the increasing incidence of the vector-borne diseases. In the first area, house construction materials are generally mud and adobe, rarely wooden with metal ceiling material. Conditions of the inner walls are mud and are not painted or plastered. Through the urban localities in the second area, construction material gradually changes to briquette and stone with smooth briquette ceiling materials. Inner walls are usually plastered and painted. In the third area, these materials for house construction are generally wooden and briquette with leaf, briquette and wooden ceiling materials. Inner walls in coastal part of the area are unplastered and unpainted but in the urban part of the area contrast with this condition. People living in the sampling site locations usually keep domestic animals such as chicken, sheep, pigs, cattle, and dogs in yard of their houses within small/big barns. Because of the locations mainly located in the rural areas, a wide variety of wild animals are also present in the surroundings. Sand fly collection Sand fly collection was performed at two different periods with CDC light traps, sticky papers and cattle-baited net trap. In the first period (between 26 July and 05 August 2005), sand flies were collected in 13 localities throughout the country while in the second period (between 20 and 26 February 2006), only 5 CL endemic localities (4 in dry zone and 1 in wet zone, highland) were chosen with an altitude ranging between 0-650 m above sea level (Table 1). In each sampling site, one or two light traps were set up inside and/or outside of houses, barracks, animal barns, etc for one or two nights. They were operated 11 or 13 h in one night between 18:00 and 07:00 h. A thermometer and hygrometer accompanied each light trap for measuring maximum and minimum values. In two sampling periods, a total of 184 light traps were set during 21 nights of trapping. Only in 5 sites (Localities 1,3,4,5, and 6), 10-20 sticky traps prepared from parchment paper (20 x 20 cm) coated with castor oil were placed in various biotopes, inside and around human dwelling and animal housing, close to the vegetation and crevices in the walls. The sticky traps were set up in the sampling site at 18:00 h and collected after 11-15 h. The cattle-baited net trap was made of white textile (rectangular synthetic/polyester; 175 mesh size and 100 deniers) with bottom windows was also used only in one location, Nikewewa. The trap was operated for 11 h, between 18:00 and 05:00 h. The sand fly specimens collected by light traps and sticky papers were transferred to 96% ethanol in the

24 February 25 February

5 6 10 26 February

22 February

4

1

Thalagoda

Nikewewa Nikewewa South Village (Athawetunuwewa) Nikaweratiya Anamaduwa

Kathaluwa

13 05 August 2006 20-23 February

Ahangama

12 05 August

31 July 31 July 01 August 02 August 02 August 02 August

5 6 7 8 9 10 Hambantota

29 July

4

Nikewewa Kokilai village Gajaba Regiment Nikewewa South Village (Athawetunuwewa) Nikaweratiya Anamaduwa Udaperadeniya Bibile, Naula Paddy field, Naula Thalagoda

11 04 August

2005 26 - 27 July 28 July 28 July

1 2 3

Locality

*CL: cutaneous leishmaniasis; P: presence; A: absence.

Wet Zone Highland Central

Dry Zone Lowland North

Wet Zone Coastal belt South

Wet Zone Highland Central

Dry Zone Lowland North

Date

No

Table 1. Study locations and collection dates in Sri Lanka.

Matale

Kurunegala Puttalum

Vavuniya

Anuradhapura

Matara

Matara

Hambantota

Kurunegala Puttalum Kandy Matale Matale Matale

Vavuniya

Anuradhapura Anuradhapura Anuradhapura

District/Province

492

60 68

80

88

13

16

0

60 68 472 599 380 492

88

88 0 80

N7.46665 E80.62324

N7.48362 E80.36237 N7.89116 E80.01215

N8.95063 E80.76102

N8.94871 E80.75764

N5.98972 E80.34984

N5.94419 E80.52372

N6.12302 E81.12719

N7.48362 E80.36237 N7.89116 E80.01215 N7.25418 E80.60894 N7.72163 E80.64547 N7.67996 E80.74460 N7.46665 E80.62324

N8.95063 E80.76102

N8.94871 E80.75764 N8.99150 E80.96072 N9.05108 E80.90063

Altitude Coordinates (Lat/Long)

P

P P

A

P

P

P

P

P P A P P P

A

P A P

CL (P/A)*

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Figure 1. Representative collection areas. A. Dry/lowland, a: typical house; B. wet/highland; C. wet/coastal.

Figure 2. Phlebotomus argentipes.A. Female pharynx (x40); B. Spermatheca and furca (x40); C. Antenna and ascoids on 3rd and 4th antennal segments (x40); D. Male genitalia (x20 and x40).

Figure 3. Phlebotomus stantoni. A. Female pharynx (x40); B. Spermatheca (x40 and x100); C. Male genitalia (x20).



field, and labeled accordingly. Specimens were cleared in lactophenol and mounted in Berlese medium on labeled slides for later identification. Before mounting, the head and genitalia of the sand flies were cut and mounted on the slides. The body parts of each specimen were kept in 96% ethanol for further molecular studies. Identification was based on the morphology of male and female genitalia using the identification keys of Theodor (1958), Lewis (1982 and 1987) and Killick-Kendrick et al. (1991). RESULTS All sand flies were caught with light traps, but none were found on sticky paper traps or cattle-baited net traps. The detailed information about trapping and temperature/ humidity during the collection period is presented in Table 2. Overall, 584 sand flies (409 in 2005 and 175 in 2006) belonging to the genera Phlebotomus (266 specimens, 2 species) and Sergentomyia (318 specimens, 8 species) were collected during two collection periods (Table 3). A total of 266 Phlebotomus were identified as P. argentipes (96.9%, 258/266) (Figure 2) and P. stantoni (3.1%, 8/266) (Figure 3). The identification studies of Sergentomyia specimens showed that there are at least 8 species according to sexes, females and males in Sri Lanka (Table 4). Because of the molecular studies for identification of Sergentomyia species are being continued, the detailed results were not presented here. A total of 76 specimens out of 266 (28.57%) were caught in three localities located in southern part of the country (Figure 4). P. argentipes was found in all localities except two (Kokilai village and Gajaba regiment), representing all geographic and climatic zones in the country.

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In the dry zone and lowland plains, 250 sand flies were collected and most of them (68.8%, 172/250) were Sergentomyia. The 97.4% (76/78) of the rest of the flies were P. argentipes while 2.6% (2/78) of them were P. stantoni. In the wet zone and central highlands, 135 sand flies were collected and most of them (78.5%, 106/135) were Phlebotomus. All Phlebotomus specimens were P. argentipes. No P. stantoni was found in these areas. The rest of the flies were Sergentomyia (21.5%, 29/135). In the wet zone and coastal belt, 199 sand flies were collected and most of them (58.8%, 117/199) were Sergentomyia. P. argentipes and P. stantoni were found as 38.2% (76/199) and 3.1% (6/199) of total sand flies, respectively. P. argentipes was the dominant species (92.7%, 76/82) among Phlebotomus species (Figure 5). DISCUSSION Phlebotomus argentipes is the known vector of L. donovani causing VL in neighboring India (Lewis and Killick 1973, Lane et al. 1990) and it has been known that only two species of Phlebotomine sand flies, P. argentipes and P. stantoni, exist in Sri Lanka but P. stantoni is not a suspected vector of Sri Lankan L. donovani (Lewis 1987). Lane et al. (1990) also reported P. argentipes as anthropophilic in central Sri Lanka, with human-biting rates similar to those reported from VL-endemic regions of India. The results of the present study showed that, P. argentipes is the predominant Phlebotomus species throughout Sri Lanka and the most probable vector species of Leishmania donovani causing CL on the island. The present study has also supported the presence of two species, P. argentipes and P. stantoni, belonging to Phlebotomus and dominancy of P.

Table 2. Information about trapping, temperature and humidity. No of traps set No of No Locality Date nights Inside Outside 1 Nikewewa 2 15 7 2 Kokilai village 1 1 3 3 Gajaba Regiment 1 8 1 July 2005 4 Athawetunuwewa 1 5 7 5 Nikaweratiya 1 1 2 6 Anamaduwa 1 3 5 7 Udaperadeniya 1 2 4 8 Bibile, Naula 1 4 1 9 Naula 1 3 0 August 10 Thalagoda 1 1 3 2005 11 Hambantota 1 6 6 12 Ahangama 1 4 2 13 Kathaluwa 1 3 3 3 16 8 1 Nikewewa 4 Athawetunuwewa 1 4 8 February 5 Nikaweratiya 1 7 5 2006 6 Anamaduwa 1 9 3 10 Thalagoda 1 6 6

Temperature (C) Max Min 32.2 26.8 34.7 24.7 36.6 25.3 33.8 24.6 31.2 24.8 39.6 22.8 33.7 20.9 29.3 21.3 29.7 22.7 29.5 26.6 33.6 23.9 27.4 25.7 30.1 26.1 29 20.3 35 17.0 31.4 24.7 36.2 21.5 37.7 21.8

Humidity (%) Max Min 93 70 91 52 93 60 96 53 93 57 95 64 92 nd 82 39 71 46 66 49 97 38 98 63 94 71 99 57 99 59 99 46 99 45 98 58


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Table 3. The results of sand fly collection in two collection periods. Total Sand P. argentipes Flies 2005 n M F M F T % 1 Nikewewa 19 15 4 1 1 2 10.52 2 Kokilai village 3 Gajaba Regiment Dry / Lowland 4 Athawetunuwewa 24 11 13 1 1 2 8.33 5 Nikaweratiya 60 30 30 27 10 37 61.66 6 Anamaduwa 12 5 7 4 1 5 41.66 7 Udaperadeniya 28 16 12 16 12 28 100.0 8 Bibile, Naula 17 11 6 11 6 17 100.0 Wet / Highland 9 Paddy field, Naula 1 1 1 1 100.0 10 Thalagoda 49 45 4 45 3 48 97.95 11 Hambantota 6 4 2 3 2 5 83.33 Wet / 12 Ahangama 60 34 26 32 19 51 85.00 Coastal 13 Kathaluwa 133 41 92 4 16 20 15.03 TOTAL 409 212 197 144 72 216 52.81 2006 1 Nikewewa 34 17 17 4 5 9 26.47 4 Athawetunuwewa 11 3 8 1 1 2 18.18 Dry / Lowland 5 Nikaweratiya 45 15 30 4 3 7 15.55 6 Anamaduwa 45 12 33 4 8 12 26.66 Wet/ 10 Thalagoda 40 7 33 7 5 12 30.00 Highland TOTAL 175 54 121 20 22 42 24.00 GRAND TOTAL 584 266 318 164 94 258 44.17 M: male; F: female, T: total.

P. stantoni

Locality

M 1 3 4

F 1 1 2

T 2 4 6

% 3.33 3.02 1.46

M 14 10 4 1 1 1 34 65

F 3 12 19 6 1 6 75 122

T 17 22 23 7 1 1 7 109 187

% 89.47 91.67 38.34 58.34 2.05 16.67 11.67 81.95 45.73

1

1 -

1 1

2.23 2.23

9 3 10 7

16 6 27 25

25 9 37 32

73.53 81.82 82.22 71.11

-

-

0 -

2

26

28

70.00

1 5

1 3

2 1.15 8 1.36

31 96

100 222

131 74.85 318 54.47

Table 4. The list of Sergentomyia species found in Sri Lanka in the present study. Sergentomyia spp. Sergentomyia insularis* Grassomyia indica S. jamesi S. arboris* S. (Parrotomyia) barraudi group I S. (Parrotomyia) barraudi group II A species close to S. jefferyi, but different from S. jefferyi A species close to S. imitor, but different from S. imitor * Previously reported species.

Sergentomyia spp.

App. % 36 25 19 3 1 8 6 1



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Figure 4. The percentage of Phlebotomus and Sergentomyia species according to geographical areas and climatic zones.

Figure 5. The comparison between altitude and sand fly density and distribution according to geographical areas and climatic zones.

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argentipes (258/584; 44.2%) among all sand flies collected. While P. argentipes was found to be widely distributed throughout the country in accordance with the previous reports (Lane et al. 1990), P. stantoni was rarely found only around jungle in the south part of the country. We used three methods for collecting sand flies, but they were captured only by CDC light traps. Cattle-baited net traps could only be used in one sampling location and could not be operated elsewhere because of logistic reasons. The failure of using sticky traps may be due to low density of sand flies in the time of collection. Among Phlebotomine sand flies, the species belonging to the Sergentomyia genus can be difficult to identify. In the genus Sergentomyia, the identification of species should be performed according to female morphology and in islands like Sri Lanka, the identification of collected Sergentomyia specimens are much more challenging, because of the probability of the presence of undiscovered species. In the two collection periods, July, 2005 and February, 2006, 318 Sergentomyia specimens (54.5% of total sand flies) were captured and first morphological identification studies showed that there are at least eight species of Sergentomyia in Sri Lanka, which is higher than previously recorded. Two Sergentomyia species out of eight are still under evaluation using conventional and molecular tools. These specimens must be compared with the types deposited in museums in London and in India to determine whether these specimens belong to species described previously. Distribution of the phlebotomine sand flies is highly disjunctive within its range, depending on local environmental factors such as precipitation and temperature, physical factors such as geographical barriers and habitat availability, and biotic factors such as the distribution and abundance of vertebrate hosts. Although altitude is not a selective factor, biotic and abiotic properties of the environment are highly correlated with altitudinal gradients, most obvious of which is climate. Our observations during the present study indicated that main climatic factors as rainfall, winds and temperature may be the most important factors effecting the distribution of sand fly species. The previous studies on ecology of sand flies showed that the altitude and bioclimatic structure has an important impact on the distribution of sand fly species (Belen and Alten 2006). The altitude is not an ecological factor by itself, but it can act on the distribution of sand flies by the diversity of habitats, relief, and by the gradient on climate that it offers. Guernaoui et al. (2006) showed that altitude was one of the most important factors on distribution and structuring sand fly species. As for most ectotherms, sand fly distribution is heavily dependent on temperature, and species situated along altitudinal gradients have to adapt to a variety of climatic conditions (Telfer and Hassal 1999). The temperature is also one of the main factors preventing the spread of both visceral and cutaneous leishmaniasis (Kuhn 1999). This ecological factor varies with the altitude according to thermal altitudinal gradient (-0.6o C/100 m). The possible

relationship between the leishmaniasis transmission and altitude may be closely related to many factors as the temperature suitable for the evaluation of Leishmania in the sand flies (Rioux et al. 1985). The altitudinal distribution and abundance of P. argentipes and other species collected from the study area are shown in Figure 5. In general, no correlation was found between altitude and sand fly densities and/or distribution of the species. On the other side, P. argentipes was collected at almost all altitudes and its distribution showed slightly positive correlation with the altitude (r=0.05). Its highest densities were registered at altitudes of 10 to 400 m. In contrast, the highest total number of sand flies was found at lower altitudes in Kathaluwa in southwest coastal area. The most sand fly specimens were collected from the altitude range of 0 to100 m. There is now evidence of an emerging epidemic of CL (534 CL cases in 2.5 years) in the southern part of the island (Rathayanake et al. 2009) where P. argentipes has the highest density. This can explain the sudden apparent increase in the number of CL cases within the island in the recent years. In Sri Lanka, L. donovani causing CL is reported to belong to the MON-37 zymodeme (Karunaweera et al. 2003), which is closely related to L. donovani MON-37, the causal agent of VL in northwest India (Alam et al. 2009). There is only one autochthonous visceral case report from Sri Lanka (Abeygunasekara et al. 2007) and zymodeme identification of Sri Lankan VL has not been reported to date. The identification of Sri Lankan VL strain(s) and a higher number of strains from CL cases using multi locus enzyme electrophoresis (MLEE) is strongly recommended, because Phlebotomus argentipes is the only probable vector of Sri Lankan CL, while it is responsible for transmitting VL in Indian subcontinent. However, some morphological variations in the local Sri Lankan P argentipes is reported, as longer length of ascoids on the fourth antennal segment of females compared with specimens from India (Lewis and Killick 1973, Lewis 1987). In India, the presence of two different local P. argentipes populations with two different morphological features was attributed to different vectorial capacities of these two morphospecies (Lane and Rahman 1980, Surendran et al. 2005). This finding is insufficient to explain the presence of morphologically different vector species responsible for VL in India and CL in Sri Lanka. Morphological differences as well as vectorial infectivity capabilities of Indian and Sri Lankan P. argentipes should be examined to clarify the situation. Hot and humid conditions have played an important role in the distribution of P. argentipes in Sri Lanka. But interestingly, in spite of the presence of optimal conditions of humidity and temperature for the development of sand flies in each part of country, in total, small numbers of sand flies were collected during both periods in July, 2005 and February, 2006. According to the results of five districts where sampling was carried out in both periods, the numbers of collected P. argentipes were dropped in the second period, from 216 in July to 42 in February. For better understanding of the seasonal activity of the sand fly populations, monthly collections should be



performed. Our finding has also been supported by the results related with the seasonal activity in the previous study (Dinesh et al. 2001). In northern Sri Lanka, Delft Island, in the middle of May in two consecutive years, 154 and 162 flies were collected, but no sand flies could be collected during similar collections in the middle of July and August (Surendran et al. 2007). Additionally, the future studies on vector bionomics, population dynamics, morphological variations and experimental infection trials using Sri Lankan L. donovani and Sri Lankan P. argentipes will be most important and essential components in the understanding of the epidemiology of the disease in the island. The transmission of visceral leishmaniasis is anthroponotic (human to human only) in India and there are no zoonotic reservoirs. The distribution of local CL cases throughout the dry zone is unlike that of a recently introduced disease. It is more likely that this is a recent recognition with increased awareness and increased risk of exposure of the population with jungle clearing, population movements, and the military activities in the north and east. Low socioeconomic status, large families, and human behavior in outdoor habits are other difficulties for applying appropriate personal protective measures. Health education, vector control and notification of the disease will be an important starting point to prevent the increase of the disease in Sri Lanka. To resolve the epidemiology of leishmaniasis in Sri Lanka, both Leishmania and the vectors require further study. For soldiers in the north and east it is an occupational hazard, and effective repellents to ward off sand fly bites are necessary. Because of recently reporting local visceral case from North Central Province, the awareness of the disease, both for public and health workers, should be maintained to prevent the spreading of the disease in the island. Establishing a disease monitoring system and continued research activities related to parasite and vector can allow the effective control of leishmaniasis in Sri Lanka. Acknowledgments This work was supported by Grant-in-Aid for Scientific Research (B) (16406007) and by Grant-in-Aid for Scientific Research (A) (19256001) from Japan Society for the Promotion of Science. The authors thank Dr. Nicole Léger for her help in the identification of Sergentomyia species. REFERENCES CITED Abeygunasekara, P.H., Y.J. Costa, N. Seneviratne, N. Ratnatunga, and M.S. Wijesundera. 2007. Locally acquired visceral leishmaniasis in Sri Lanka. Ceylon. Med. J. 52: 30-31. Alam, M.Z., C. Haralambous, K. Kuhls, E. Gouzelou, D. Sgouras, K. Soteriadou, L. Schnur, F. Pratlong, and G. Schonian. 2009. The paraphyletic composition of Leishmania donovani zymodeme MON-37 revealed by multilocus microsatellite typing. Microbes Infect 11:

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