Sand Fly (Psychodidae: Phlebotominae) Ecology of an Emerging Cutaneous Leishmaniasis Focus in Khyber Pakhtunkhwa with an Updated Species Checklist from Pakistan

Syed Basit Rasheed*, Farrah Zaidi, Samiullah and Tehmina Jan

Vector Biology and Entomology Section, Institute of Zoological Sciences, University of Peshawar, Peshawar 25120. Pakistan.

ABSTRACT

Leishmaniasis, an important neglected vector borne disease, endemic in the northern parts of Pakistan. The disease mainly exist in cutaneous form while sporadic cases of visceral leishmaniasis has also been reported from the affected areas. Present study was designed to know the species composition, relative abundance and seasonal variation of leishmaniasis vector in an emerging endemic focus of Nowshera. Sand flies collected by flit method were identified into 4 species of genus Phlebotomus and 17 species of genus Sergentomyia. P. sergenti, the suspected vector of leishmaniasis was also collected in this survey. Sergentomyia baghdadis and S. babu were the most abundant species and sand fly active season extended from March to November with a unimodal distribution and population reaching its peak during the month of August. A supplementary collection from Charun area of Chitral revealed 12 species of Phlebotomus and four species of Sergentomyia. Among the total 31 species collected from both areas, six species of Phlebotomus (P. angustus, P. comatus, P. kabulensis, P. rupester, P. turanicus and P. newsteadi) collected from Chitral and a single species of Sergentomyia (S. sagodina) collected from Nowshera are new reports to Pakistan. Current study also added subgenus Kasaulius to the Phlebotomus of Pakistan. With the addition of these seven species, the checklist of sand flies of Pakistan has increased to 50 species, checklist provided.

Article Information

Received 19 December 2022

Revised 26 December 2022

Accepted 24 January 2023

Available online 29 April 2023

(early access)

Published 21 May 2024

Authors’ Contribution

SBR conceived and designed the study and wrote the article. SBR and FZ supervised the research projects. Samiullah and TJ collected the specimens as part of undergraduate research project. SBR, Samiullah and TJ identified the specimens. FZ edited the manuscript.

Key words

Sand fly, Diversity, Ecology, Checklist, Phlebotomus, Cutaneous leishmaniasis

DOI: https://dx.doi.org/10.17582/journal.pjz/20221219171215

* Corresponding author: [email protected]

0030-9923/2024/0004-1589 $ 9.00/0

Copyright 2024 by the authors. Licensee Zoological Society of Pakistan.

This article is an open access article distributed under the terms and conditions of the Creative Commons Attribution (CC BY) license (https://creativecommons.org/licenses/by/4.0/)

INTRODUCTION

Leishmaniasis is a growing vector borne parasitic multi host neglected tropical disease with 350 million people at risk of contracting the disease. Approximately 12 million people get infected yearly with this disease that occur in three clinical forms in human i.e., visceral leishmaniasis (VL), mucocutaneous leishmaniasis (MCL) and cutaneous leishmaniasis (CL) affecting the visceral organs, mucous membrane and skin, respectively. CL is the most common form that causes skin lesions, leaving lifelong scars on exposed parts of the body. An estimated 1 million cases annually occur around the globe, 85% of which occurs in 10 countries: Algeria, Afghanistan, Brazil, Bolivia, Colombia, Iran, Iraq, Syria, Tunisia and Pakistan (Ruiz-Postigo et al., 2021).

Leishmaniasis is an emerging vector borne disease in Pakistan too. Cases have been reported from all four provinces i.e., Punjab, Sindh, Khyber Pakhtunkhwa (KP), Balochistan and from Gilgit-Baltistan and Kashmir but KP province has the most affected areas of the country. Leishmaniasis is endemic in all seven newly merged districts of KP (previously known as Federally Administered Tribal Area or FATA) with more than 42000 cases reported from district Khyber only during the past one decade. According to WHO cases have been reported from Malakand, Mardan, Nowshera, Bannu, Karak and all merged tribal districts of KP with disease burden mounting to 40,000 cases in 2019 (Ruiz-Postigo et al., 2021).

Sand flies are small hematophagous insects responsible for the transmission of leishmaniasis, bartonella and arboviruses. There are approximately 1000 species of sand flies in which 540 occur in new world and 460 in old world (De Sousa-Paula, 2021). Only 98 of these species act as vectors of human leishmaniasis, 56 of which belong to genus Lutzmoyia in the new world and 42 to genus Phlebotomus in the old world (Maroli et al., 2013). Species of sand flies such as Phlebotomus sergenit and P. papatasi are proven vectors of anthroponotic CL and zoonotic CL in the old world respectively, while P. salehi and P. caucasicus have been incriminated or marked as suspected vectors of leishmaniasis in different parts of the world (Ajaoud et al., 2013; Es-Sette et al., 2014; Azizi et al., 2012). Though importance of sand flies is well established across the world but in Pakistan little work has been done on the systematics of these medically important insects. Few studies have been conducted to investigate the sand fly fauna of leishmaniasis affected areas in Pakistan (Qutubudin, 1951; Nasir, 1958; Barnett and Suyemota, 1961; Ahmad et al., 1960; Lewis, 1967; Burney et al. 1981; Burney, 1986; Munir, 1994).

Lewis (1967) reported 27 (10 Phlebotomus and 17 Sergentomyia) species of sand flies from Pakistan. Later Munir (1994) collected eight species of Phlebotomus from Northern areas of Pakistan. Aslamkhan et al. (1998) published a check list of sand flies of Pakistan reporting 29 species from Pakistan. Kakarsulemankhel (2003) collected P. bergeroti, P. papatasi and Phlebtomous salehi from Balochistan and then published a checklist of sand flies of Balochistan with six new reports from Balochistan and Pakistan (Kakarsulemankhel, 2004), Ali et al. (2016a) worked on the diversity of sand flies of Dir and reported 20 species. Ali et al. (2016b) while exploring the sand fly fauna of North Waziristan reported 14 species of sand flies.

Current study was conducted to investigate the sand fly fauna of an emerging leishmaniasis focal point in KP. Knowledge of distribution and abundance of vectors can provide useful information to devise a control strategy to prevent the spread of disease in endemic areas. This study was designed to know the species composition, relative abundance and seasonal variation in two villages of district Nowshera. Additionally, a supplementary collection was carried out from district Chitral, an area located in the Hindukush Mountain range in the north of KP, to gather some preliminary information regarding the sand flies occurring in the area. This paper also provided an updated checklist of sand fly fauna of Pakistan.

MATERIALS AND METHODS

Study area

Nowshera is a district in KP located along the river Kabul. The district consists of 03 tehsils and 47 Union Councils covering an area of 1748 sq km, it lies between latitude 33º42, to 34º09’ N and longitude 71º41’ to 72º 15’ E. The climate of district Nowshera is warm and sub-humid with an average temperature of 30ºC. In summer the weather is too hot as it touches 40ºC to 45ºC, while in winter the weather is too cold as sometimes it can be as low as 1ºC. The area receives an average rainfall of 513 mm/year. The area receives maximum rainfall in the months of February, March, July and August.

Collection methods

A year-round collection of sand flies was performed from December to November in the Manki Shareef and Nizampur areas of district Nowshera (Fig. 1). From each village 15 houses were selected and the collection was performed on monthly basis by flit method. Sand flies were collected from two types of habitats Human dwellings and Animal rooms. The supplementary collection was carried out from Charun area of District Chitral (Fig. 1) by CDC miniature light traps.

 

Flit method

Indoor sand fly collection was carried out by flit method (Lane and Crosskey, 1993). The rooms from where collection was done were either muddy or cemented, but majority of the rooms were cemented. The rooms were of two types based on the basis of usage i.e., animals rooms and human inhabiting rooms. The rooms floors were cleared and white sheets were spread to cover the floor area. Aerosol insecticide spray (Pyrethroids) of various brands (Zendin and Kingtox) was performed for 30 sec and then the room was kept airtight and locked for 10-15 min, for the insecticide to kill any sand fly in the room. After 10 min, the room was opened and sheets were searched for any sandfly killed by the insecticide spray. Using fine entomological forceps the sandflies were carefully transferred to Eppendorf tubes containing 70% ethanol for preservation . The sandflies were kept in the alcohol at room temperature until the identification of the specimens up to species level.

CDC miniature light traps

In Charun area of Chitral battery operated CDC miniature Light Traps (model 512 with air-actuated gate system and LCS-2 photo switch; John W. Hock Company, USA) were hung inside a human dwelling room 30 inches above ground from dusk to dawn to collect sand flies. At dawn the sand flies were collected by fine entomological forceps and preserved in 90% Ethanol.

Mounting and identification sand flies

Sand flies were identified based on internal anatomy which can be only visible if they are mounted permanently on slide. For this purpose, a sand fly was transferred to a glass slide and air-dried to remove any alcohol present in it. The head of the sand fly was detached from the body with the help of fine needle under a stereo microscope (Olympus, SD 30, USA) and positioned, so that dorsal side is visible. The thorax and abdomen were also placed in a position so that all anatomical structures were easily visible. A drop of Puri’s media was added to the slide and then covered with cover slip. The cover slip was pressed gently to remove any air bubbles from the media. The slides were left for two weeks to clear the internal anatomy of the specimens. Sand flies were identified under binocular microscope (Nikon E-100) using species identification key described by Lewis (1967) and Artemiev (1978).

Data analysis

Relative abundance and seasonal variation among various species were calculated in Excel, while correlation coefficient of bioclimatic variables with abundance was calculated by using online statistical software (Wessa, 2017).

RESULTS

A total of 5894 specimens of sand flies were collected from Nowshera and Chitral comprising 31 species belonging to two genera Phlebotomus and Sergentomyia. Phlebotomus was represented by six subgenera and 14 species while Sergentomyia was represented by five subgenera and 17 species (Table I). Collection from Charun area of Chitral comprised of 16 species classified into two genera and six subgenera. Phlebotomus was having 12 species, while Sergentomyia was represented

 

Table I. List of Phlebotomine of Pakistan and the sites of collections Chitral (C) and Nowshera (N).

Names of species	Site of collection
	N	C
1. Genus Phlebotomus Rondani and Bert, 1840
A. Subgenus Adlerius Nitzulescu, 1931
1. P. (Ad.) angustus Artemiev, 1978	-	
2. P. (Ad.) comatus Artemiev, 1978	-	
3. P. (Ad.) hindustanicus Theodor, 1958
4. P. (Ad.) kabulensis Artemiev, 1978	-	
5. P. (Ad.) longiductus Parrot, 1928	-	
6. P. (Ad.) rupester Artemiev, 1978	-	
7. P. (Ad.) salangensis Artemiev, 1978	-
8. P. (Ad.) turanicus Artemiev, 1974	-	
B. Subgenus Anaphlebotomus
9. P. (An.) colabaensis Young and Chalam, 1927
C. Subgenus Kasaulius
10. P. (K.) newsteadi (Sinton, 1926)	-	
D. Subgenus Euphlebotomus Theodor, 1948
11. P. (E.) argentipes Annandale and Brunetti, 1908
E. Subgenus Larroussius Nitzulescu, 1931
12. P. (L.) kandelakii burneyi Shurenkova, 1929
13. P. (L.) keshishiani Shurenkova, 1936	-	
14. P. (L.) major major Annandale, 1910
F. Subgenus Paraphlebotomus Theodor, 1948
15. P. (Para.) alexandri Sinton, 1928		-
16. P. (Para.) andrejevi Shakrizjanova, 1953
17. P. (Para.) caucasicus Marzinovyskyi, 1917
18. P. (Para.) kazeruni Theodor and Mesghali, 1964		-
19. P. (Para.) nuri Lewis, 1967
20. P. (Para.) sergenti Parrot, 1917		-
G. Subgenus Phlebtomus Rondani and Brete, 1940
21. P. (P.) bergeroti Parrot, 1934
22. P. (P.) papatasi (Scopoli, 1786)		
23. P. (P.) salehi Mesghali, 1965
H. Subgenus Synphlebotomus Theodor, 1948
24. P. (Sy.) ansari Lewis, 1958	-	
25. P. (Sy.) eleanorae Sinton, 1931	-	
2. Genus Sergentomyia Franca and Parrot, 1920
A. Subgenus Grassomyia Theodor, 1958
26. S. (G.) dreyfussi turkestanica Theodor and Mesghali, 1964		-
27. S. (G.) indica (Theodor, 1931)		-
Table continued on next page.................
Names of species	Site of collection
	N	C
B. Subgenus Parratomyia Theodor, 1958
28. S. (Parr.) africana (Newstead, 1912)
29. S. (Parr.) babu (Annandale, 1910)		
30. S. (Parr.) baghdadis (Alder and Theodor, 1929)		-
31. S. (Parr.) bailyi (Sinton, 1931)		
32. S. (Parr.) freetownensis Sinton, 1930
33. S. (Parr.) grekovi (Chodukin, 1929)		
34. S. (Parr.) montana (Sinton, 1924,)		
35. S. (Parr.) palestinensis (Alder and Theodor, 1927)		-
36. S. (Parr.) sogdiana (Parrot, 1929)		-
37. S. (Parr.) shortii (Adler and Theodor, 1927)
38. S. (Parr.) sumbarica (Perfiliew, 1933)		-
C. Subgenus Neophlebotomus Franca and Parrot, 1920
Randanomyia Theodor, 1958
39. S. (Neo.) hodgsoni hodgsoni (Sinton, 1933)
40. S. (Neo.) hodgsoni pawlowskyi (Perfiliew, 1933)		-
D. Subgenus Sergentomyia Franca and Parrot, 1920
41. S. (Ser.) dentata (Sinton, 1933)
42. S. (Ser.) fallax afghanica Artemiev, 1974		-
43. S. (Ser.) mervynae Pringle, 1953		-
44. S. (Ser.) murgabiensis (Perfiliew, 1939)
45. S. (Ser.) punjabensis (Sinton, 1927)
46. S. (Ser.) theodori (Parrot, 1942)		-
E. Subgenus Sintonius Nitzulescu, 1931
47. S. (Sin.) christophersi (Sinton, 1927)
48. S. (Sin.) clydei (Sinton, 1928)		-
49. S. (Sin.) hospitii (Sinton, 1929)		-
50. S. (Sin.) tiberiadis pakistanica (Alder, Theodor and Lourie, 1930)		-

 

by four species. Collection from Nowshera comprised of 5424 sand flies classified into four species in two subgenera of Phlebotomus (P. papatasi, P. sergenti, P, kazeruni and P. alexandri) and 17 species in 5 subgenera of Sergenotmyia (S. babu, S. baghdadis, S. fallax afghanica, S. indica, S. bailyi, S. mervynae, S. hodgsoni pawlowskyi, S. tiberiadis pakistanica, S. hospitii, S. grekovi, S. clydei, S. montana, S. sumbarica, S. sogdiana, S. palestinensis, S. dreyfussi turkestanica and S. theodori) (Table I). Majority of the collection was represented by Sergentomyia with S. baghdadis being the most dominant species followed by S. babu, S. fallax afghanica and S. bailyi (Table II).

 

Table II. Relative abundance of sand fly species collected from Nowshera and Chitral.

S. No	Species	Nowshera		Chitral
		♀, ♂	Relative abundance	♀, ♂	Relative abundance
1	Ph. papatasi	96, 80	3.24	339, 62	85.3
2	Ph. sergenti	74, 136	3.87	12, 20	6.8
3	Ph. kazeruni	2, 2	0.07	–
4	Ph. alexandri	0, 8	0.15	–
5	Ph. keshishiani	–		2, 3	1.06
6	Ph. longiductus	–		2, 0	0.43
7	Ph. ansari	–		3, 0	0.64
8	Ph. angustus	–		1, 3	0.85
9	Ph. rupester	–		1, 0	0.2
10	Ph. newsteadi	–		0, 1	0.2
11	Ph. eleanorae	–		2, 0	0.43
12	Ph. kabulensis	–		6, 1	1.49
13	Ph. turanicus	–		2, 1	0.64
14	Ph. comatus	–		1, 0	0.2
15	S. babu	1210, 632	33.96	1, 1	0.43
16	S. baghdadis	1760, 846	48.04	–
17	S. fallax afghanica	102, 138	4.42	–
18	S. indica	2, 36	0.7	–
19	S. bailyi	138, 46	3.39	2, 2	0.85
20	S. mervynae	4, 2	0.11	–
21	S. hodgsoni pawlowskyi	32, 2	0.63	–
22	S. tiberiadis pakistanica	0, 4	0.07	–
23	S. hospitii	6, 2	0.15	–
24	S. grekovi	24, 4	0.52	1, 0	0.2
25	S. clydei	4, 2	0.11	–
26	S. montana	4, 6	0.18	1, 0	0.2
27	S. sumbarica	0, 2	0.04	–
28	S. sogdiana	2, 2	0.07	–
29	S. palestinensis	2, 6	0.15	–
30	S. dreyfussi turkestanica	4, 0	0.07	–
31	S. theodori	2, 0	0.04	–
	Total	5424		470

 

Phlebotomus was represented by only 7.33% of the total collection with P. sergenti being the most dominant species of the genus followed by P. papatasi (Table II). A supplementary collection from Charun area of Chitral by light traps yielded 470 specimens belonging to 16 species of Phlebotomus and Sergentomyia. Phlebotomus was represented P. papatasi, P. sergenti, P. keshishiani, P. longiductus, P. ansari, P. angustus, P. rupester, P. newsteadi, P. eleanorae, P. kabulensis, P. turanicus and P. comatus while Sergentomyia was represented by S. babu, S. bailyi, S. grekovi and S. montana (Table I).

The year around collection made from District Nowshera has shown that abundance of sand fly was minimum during the cold months and maximum during the warm rainy season (Monsoon season from July to September). An increase in sand fly density was observed with temperature, precipitation and humidity (Fig. 2). No specimens of sand fly were reported during the month of January and February, however sand flies started appearing during the month of March and April, but abundance was low. Population started building up in May and then a sudden increase was observed from July to September with a peak abundance observed in the month of August, then a sudden decrease was observed in the month of October and only few specimens were reported in November and none in the cold month of December (Fig. 2). Correlating the abundance with climatic variables has shown a positive correlation with temperature, humidity and precipitation, however, this correlation was significant with temperature and precipitation only (P < 0.05).

 

Current study for the first time from Pakistan reported one new subgenus i.e. Kasaulius and six new species of Phlebotomus i.e. P. angustus, P. rupester, P. kabulensis, P. turanicus, P. newsteadi and P. comatus from Chitral and one new species of Sergentomyia i.e. S. sogdiana from Nowshera. Four of the Phlebtomous species i.e., P. angustus, P. rupester, P. kabulensis and P. turanicus belonged to subgenus Adlerius, while P. newsteadi and P. comatus were from subgenera Kasaulius and Synphlebtomous, respectively. S. sogdiana belonged to subgenus Parratomyia of Sergentomyia genus. With the addition of these seven species now the sand fly fauna of Pakistan comprises of 50 species, of which 25 species each belonging to Phlebotomus and Sergentomyia are listed in Table I which also shows sand flies collected from Nowshera (N) and Chitral (C).

DISCUSSION

There has been regular reports of leishmaniasis from the northern parts of Pakistan since the beginning of this century. The northwestern province of Khyber Pakhtunkhwa has been one of major hotspots of leishmaniasis in Pakistan for last more than one decade. The present study area has been one of the leishmaniasis hotspots in the province. The disease has been endemic in certain parts of the affected areas especially the tribal belt while epidemics or sporadic infections have been reported from areas like in various parts of district Nowshera, Bannu, Lakki Marwat and Karak in KP. Very few studies have been conducted to know the species composition, relative abundance and seasonal variation of sand flies in Pakistan. Some of these studies were conducted on large scale (Lewis, 1967; Munir, 1994; Aslamkhan et al., 1998; Kakarsulemankhel, 2004), while few had been carried out on a local scale in some districts of Pakistan (Kakarsulemankhel, 2003; Ali et al., 2016a, b; Wahid et al., 2020). An epidemic of the diseases had been reported from Manki Shareef and Nizampur areas of district Nowshera. One year sand fly collection from the affected area revealed that the suspected leishmaniasis vectors in Pakistan i.e., P. papatasi and P. sergenti both were occurring in the study area. The species were also collected from Chitral district. Both these species have been reported by Munir (1994) from hilly areas of northern Pakistan, Azad and Jammu Kashmir and Islamabad, from various parts of KP and Punjab (Aslamkhan et al., 1998), from Balochistan (Kakarsulemankhel, 2003, 2004) and in KP from Dir Upper and Lower (Ali et al., 2016a) and tribal district of North Waziristan (Ali et al., 2016b).

P. sergenti had been incriminated as vector of L. tropica in Iran (Oshaghi et al., 2010; Aghaei et al., 2014), Saudi Arabia (Al-Zahrani et al., 1988), Syria (Haddad et al., 2015), Turkey (Limoncu et al., 2020) and Morocco (Mhaidi et al., 2018), while it has been considered as suspected vector of cutaneous leishmaniasis in Pakistan (Rowland et al., 1999). The present study area of Nowshera faced an epidemic of cutaneous leishmaniasis before this entomological survey and presence of vector species confirms the presence of disease spreading agent in the study area. During the study period both suspected vector i.e., P. papatasi and P. sergenti were less abundant and was represented by only 3.24% and 3.87%, respectively of the total collection. In contrast to current work, studies conducted in the merged tribal districts of North Waziristan (Ali et al., 2016a) and Bajaur (Wahid et al., 2020) reported high abundance of P. sergenti and other Phlebotomus species as compared to Sergentomyia, but similar observations had been reported from the settled districts of Dir Upper and Lower. High relative abundance of P. sergenti had been reported from leishmaniasis endemic areas of Egypt (El-Sawaf et al., 1987) and Morocco (Faraj et al., 2013; Boussaa et al., 2016). In Pakistan presence of high abundance of P. sergenti could have been the possible reason that the merged tribal districts are reporting cases of leishmaniasis regularly for last more than one decade, while sporadic cases were reported from the Afghan refugee camp in Dir during late 90’s only (Rowland et al., 1999) and a single epidemic in the study area before conduction of current entomological survey.

Our study has reported a unimodal distribution of sand flies in district Nowshera with active season extending from March to November. S. babu was collected throughout the active season while P. papatasi, P. sergenti and S. baghdadis were reported from March to October. Seasonal activity of sand flies is influenced by abiotic factors like temperature, rainfall and relative humidity (Maroli et al., 2013). In Pakistan temperature start rising in the month March and favorable temperature generally remains till October and in microhabitats till the start of December. In the hilly areas of Pakistan with cold environmental conditions, shorter active season had been reported for sand flies. In the tribal district of North Waziristan the active season extends from April to September (Ali et al., 2016a), in Dir upper and lower this period extends from May to October (Ali et al., 2016b) and from June to October in the tribal district of Bajaur (Wahid et al., 2020). In Nowshera sand fly population was high during the month of July to September, peaking in the month of August when the temperature is between 35 to 40°C and humidity is high. As these two factors mainly influence the density of sand fly (Gebresilassie et al., 2015), and both these factors remain ideal during the monsoon season from July to September in Pakistan thus explaining the high density and unimodal distribution of sand flies in the study area. Similarly, other studies carried out in Pakistan had reported peak seasonal activity in the months of July (Ali et al., 2016a; Wahid et al., 2020) and August (Ali et al., 2016b), which coincide with the monsoon season in the country providing ideal conditions for the sand flies to thrive and multiply.

In this study we reported 31 species from two districts of Pakistan i.e., Nowshera and Chitral. Four Phlebotomus and 17 Sergentomyia species were collected from Nowshera, while 13 Phlebotomus and four Sergentomyia from Chitral. Majority of these species had already been reported from Pakistan in previous studies (Lewis, 1978; Munir, 1994; Aslamkhan et al., 1998; Ali et al., 2016a, b; Wahid et al., 2020) but six Phlebotomus species collected from Chitral and one species of Sergentomyia collected from Nowshera are new reports from Pakistan. To date researchers have reported the presence of 37 sand fly species in Pakistan (Zaidi et al., 2017; Wahid et al., 2020), however, literature have shown a different figure. Lewis (1967) reported presence of 10 Phlebtomous and 17 Sergentomyia species and predicted presence of P. bergeroti, P. eleanorae, P. jacusieli, P. modfidii, P. mongolensis, P. newsteadi, P. salehi, S. sintoni, and S. zeylanica in Pakistan and some of these were then reported in surveys later conducted in various parts of the country. Munir (1994) further added two species i.e., P. hindustanicus and P. salangensis to this checklist increasing the number of sand fly species to 29 from Pakistan. A large-scale spatial survey further reported three new species from Pakistan, which were P. eleanorae and P. salehi as predicted by Lewis (1967) and S. hodgsoni hodgsoni increasing sand fly species number to 32 (Aslamkhan et al., 1998). A survey in Balochistan reported P. bergeroti (Kakarsulemankhel, 2003) and a checklist of sand fly of Balochistan further added six new species raising the number of species to 39 (Kakarsulemankhel, 2004). A study conducted in tribal district of North Waziristan reported P. caucasicus and S. sumbarica for the first time from Pakistan (Ali et al., 2016a) and P. ansari and P. kazeruni reported from district Dir were also the first report of these species from Pakistan. To date literature reports 43 species of sand flies comprising of 19 species of Phlebotomus and 24 species of Sergentomyia. Present study reports six species of Phlebotomus from Chitral and one species of Sergentomyia from Nowshera for the first time from Pakistan, thus increasing the checklist of sand fly fauna of Pakistan to 50 species.

Sergentomyia is classified into six subgenera (Artemieve, 1978) and except Parvidens all occur in Pakistan. Phlebtomus is subdivided into 11 subgenera (Lewis, 1982) and eight of them occur in Pakistan, while Spelaeophlebotomus, Idiophlebotomus and Australophlebtomus have not been reported from Pakistan, as they are confined to African, East Asian and Australian regions respectively (Lewis, 1982). All four subgenera of Phlebotomus involved in the transmission of leishmaniasis i.e., Euphlebotomus, Larroussius, Paraphlebotomus and Phlebotomus occur in Pakistan, which explains the occurrence of anthroponotic cutaneous leishmaniasis, zoonotic cutaneous leishmaniasis and visceral leishmaniasis in Pakistan (Khan et al., 2021). Kasaulius (Lewis, 1982) reported for the first time from Pakistan is represented by a single species P. newsteadi. Theodor (1948) provisionally placed this species in subgenus Euphlebotomus but Lewis (1978) suggested it to be outside this subgenus and placed it in the newly described subgenus Kasaulius (Lewis, 1982). This species had been previously reported from India only. Adlerius was previously represented by three species in Pakistan and our study further adds five more species to this subgenus.

Sand flies have cosmopolitan distribution and are distributed worldwide (Andrade and Brazil, 2003). India, the eastern neighbouring country of Pakistan lies in Oriental region, its sand fly fauna consists of 46 species with 11 species belonging to genus Phlebotomus and 35 species to genus Sergentomyia (Lewis, 1978; Ranganathan and Swaminath, 2015). Both neighbouring countries share 21 species of sand fly. Afghanistan the westerly neighbouring country of Pakistan lies in Palearctic region. 44 species had been reported from Afghanistan, consisting of 22 identified and 2 unidentified species of Phlebotomus and 20 species of Sergentomyia (Artemieve, 1978). Both countries share 39 sand fly species with P. caudatus and P. zulfagarensis not been reported from Pakistan, while P. ansari, P. argentipes, P. bergeroti, P. colabaensis, P. eleanorae, P. newstedi, S. africana, S. bailyi, S. freetownensis, S. punjabensis and S. shortii not collected from Afghanistan. Literature shows very few studies on the diversity and ecology of sand flies in both these countries and filling these gaps may increase the number of sand fly species occurring in these countries.

Lot of work has been done on the sand fly fauna of Iran and the checklist have 56 species reported from Iran (Kasiri et al., 2000; Zhraei-Ramazani et al., 2013; Kassiri et al., 2011). Both countries share 16 species of Phlebtomous and 17 species of Sergentomyia. Nine species each of Phlebtomus (P. hidndustanicus, P. angustus, P. rupester, P. turanicus, P. comatus, P. colabaensis, P. newsteadi, P. argentipes, P. nuri) and 8 species of Sergentomyia (S. babu, S. shortii, S. montana, S. freetownensis, S. punjabensis, S. fallax afghanica, S. murgabiensis, S. hospitii) collected from Pakistan has not been reported from Iran, while 16 species of Phlebotomus (P. blcanicus, P. brevis, P. halepensis, P. mesghali, P. nadimi, P. ilami, P. langeroni, P. mascittii, P. perfiliewi, P. simrnovi, P. tobbi, P. wenyoni, P. jacusieli, P. mongolensis, P. chinensis, an unidentified species of subgenus Paraphlebotomus) and 7 species of Sergentomyia (S. squamipleuris, S. iranica, S. dolichopus, S. antennata, S. sintoni, S. alderi and an unidentified species of subgenus Neophlebotomus) reported from Iran (Kasiri et al., 2000) have not been observed in Pakistan. All six subgenera of Phlebotomus present in Iran are also reported from Pakistan but Anaphlebotomus and Kasaulius are reported only from Pakistan. Similarly, Iran has all six subgenera of Sergentomyia but subgenus Parvidens is absent in Pakistan.

In the old world, Iran has reported maximum number of sand flies followed by Pakistan, India and Afghanistan. China has reported 42 (16 Phlebtomous and 26 Sergentomyia) species (Leng and Zhang, 1993). Kasap et al. (2019) gave a checklist of 28 species of sand flies from Turkey, 22 species have been reported from Palestinian territory (Sawalha et al., 2017), 21 from Jordon (Kamhawi et al., 1995), 14 from Egypt (El Sawaf et al., 1987) and 11 species have been reported from Morocco (Boussa et al., 2016). Pakistan shares 2,670 km boundary known as Durand line with Afghanistan and only two species reported from Afghanistan are not present in Pakistan because both these species occur in the west of Afghanistan. Iran also shares boundary with the Balochistan region of Pakistan and 23 species reported from Iran have not been collected from Pakistan. Among these species 5 species i.e., P. halepensis, P. mesghali, P. mongolensis, S. iranica and S. sintoni has been reported from regions less than 200 kms from Pakistan border. A detailed survey near the Iranian border region of Pakistan may reveal the presence of these species in Pakistan. Similarly, Pakistan also shares a lengthy easterly border with India. Majority of species reported from India have not been collected from Pakistan. Species like S. eadithae, S. siroi, S. zeylnica, S. kauli and S. himalayensis that occur in the areas near Pak-India border could be expected to occur in Pakistan.

Conclusion

In Pakistan few detailed spatial and temporal studies on the diversity of sand flies have been conducted. This study provided a checklist of 50 species of sand flies from Pakistan but detailed surveys of unexplored areas from all over the country may add more species to this list. Further studies will not only enhance the knowledge regarding the diversity of sand flies in Pakistan but will also contribute to the knowledge regarding the vector species that could transmit various form of leishmaniasis in human population.

Acknowledgements

The authors are also thankful to the health department of District Nowshera and to the residents of District Chitral and Nowshera for their cooperation in conducting entomological survey in the study area.

Funding

Funds for this study were provided by Higher Education Commission under project No NRPU-4135.

IRB approval and ethical statement

This study was reviewed, approved and monitored by the “Ethical Committee” Faculty of Life & Environmental Sciences, University of Peshawar, under applicant certificate number (12/EC/F.LIFE-2020).

Statement of conflict of interest

The authors have declared no conflict of interest.

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