Revised checklist and distribution maps of Anopheles ( Insecta : Diptera : Culicidae : Anophelinae ) mosquitoes of Bangladesh

this work, it has been 25 years since the publication of the first checklist of mosquito in Bangladesh and several significant taxonomic changes have occurred (e.g., species name changes, a variety changed to a species, and one species divided into many varieties). In addition, several new species distribution records for a number of different species have been recorded. Considering these changes, it seems appropriate to prepare an updated list of Anopheles species in Bangladesh along with their up-to-date distribution maps.


Introduction
On a global scale, Anopheles mosquitoes are well known as annoying biting pests and vectors of human and animal pathogens with malaria being the most important infection in terms of human morbidity and mortality.Some species of Anopheles can also transmit canine heartworm Dirofilaria immitis, filariasis-causing species such as Wuchereria bancrofti and Brugiamalayi, and viruses (Lehrer 2010).In Bangladesh, malaria is the most important human pathogen transmitted by Anopheles mosquitoes and there are seven known vector species.
Anopheles mosquitoes have been reported from different parts of British India (including the area that would eventually become Bangladesh) before the partition in 1947 (James and Liston 1911;Covel 1927;Covel 1931;Barraud 1933;Christophers 1933;Puri 1936;Puri 1948).After the partition of India, Quraishi andTalibi (1956) accumulated the records of mosquitoes collected by different researchers and reported 31 species of Anopheles from the then East Pakistan (which is now an independent Bangladesh).Plan of Operation of Malaria Eradication Program, MEP (1960) of Bangladesh reported 25 species of Anopheline mosquitoes.After the independence of Bangladesh in 1971, several researchers actively surveyed the mosquito species present in the country (Aslamkhan and Wolfe 1972;Khan and Talibi 1972;Ameen and Moizuddin 1973;Rosenberg 1983).Ahmed (1987) summarized Mosquito fauna of Bangladesh for the first time and this list included 32 species and 2 varieties of Anopheles mosquitoes.A number of other reports (Ahmed et al. 2004;Bashar 2006;Jannat and Ahmed 2006;Ahmed et al. 2009;Alamet al. 2010;Jannat and Ahmed 2010;Chowdhury et al. 2011;Alam et al. 2012;Bashar et al. 2012a,b;) on mosquitoes from across Bangladesh are available since this first report.Despite Abstract: It has been 25 years since the publication of the first checklist of mosquito in Bangladesh and several significant taxonomic changes have occurred.Therefore, considering these changes, we prepare an updated list of Anopheles species in Bangladesh along with their distribution maps.A total of 36 Anopheles species have been listed from Bangladesh and these species belong to either the sub-genus Anopheles or Cellia but we captured 30 species in our study.Eleven species were distributed all over Bangladesh but Anopheles nivipes and An.turkhudi were found only in Bandarban and Cox's Bazar areas respectively.Anopheles sundaicus were found limited number in the costal belt of Bangladesh.Nearly all Anopheles species were found in Southeastern hilly parts of Bangladesh.However, An. vagus, An. philippinensis, An. barbirostris distribute all over the Bangladesh with high density.
Netrokona, Moulvibazar and Manikgonj districts (Figure 1).Adult mosquitoes were collected using light traps (LTs), pyrethrum spray (PS), and human bait (HB) following the World Health Organization procedures (WHO1975).LTs were hanged 1.5 meter above the ground level in inside and outside of the houses.HB catch were also done in inside and outside the houses.Larvae were collected using standard, 400 ml-capacity dipper; an eyedropper; turkey baster, tea strainer, modified bilge pump, white enamel plate, vials.Collected larvae and adult mosquitoes were killed with formaldehyde and chloroform respectively and identified morphologically in the field laboratory under stereoscopic microscopes within 12 hour after collecting samples using standard taxonomic keys (Christophers 1933;Puri 1960;Harrison and Scanlon 1975).Collected samples were transported to the Entomology Laboratory at Jahangirnagar University for the double-checking of species identification.
Species density of the mosquito was calculated according the number of mosquitoes collected in indoor and outdoor using light traps.In maps we showed low (per light trap per night capture <1), medium (per light trap per night capture 1-5) and high (per light trap per night capture >5) density in the maps.Infection rate is the malaria morbidity per thousand people.

Results and Discussion
A total of 36 Anophelines species have been listed from Bangladesh, and these species belong to either the subgenus Anopheles or Cellia.Our research teams were able to confirm 30 of these species from the different regions of Bangladesh and an asterisk (Table 1) indicates these species.The classification scheme follows Knight and Stone (1977) and Knight (1978) and genera, sub-genera and species were arranged alphabetically in table 1.
Malaria is endemic to Bangladesh and vector diversity and density are very high.Total 13 out of 64 districts bordering India and Myanmar are severely affected by malaria (Bashar et al. 2012a).Among these, the districts of Chittagong, Rangamati, Khagrachari, Bandarban, and Cox's Bazar are hyper endemic, whereas the districts of Kurigram, Sherpur, Mymensingh, Netrokona, Sylhet, Sunamgonj, Moulvibazar, and Hobiganj are prone to lowlevel epidemics.Seven Anopheles species are the confirm vector in Bangladesh and there are more six species are suspected (Alam et al. 2010;Bashar et al. 2012a, b).
Since the 1930s, several researchers collected different species of Anopheles mosquitoes from Bangladesh.We recorded 30 Anophelines species during our study.Quraishiand Talibi ( 1956) reported 31species of Anopheles and they describe An. annandalai, An. insulaeflorum, An. lindesayi.However, these species never reported in Bangladesh by other researchers.These mosquitoes were collected from different region of Pakistan where the geography and environment are not same with Bangladesh.Aslamkhan (1971) recorded 27 species and 2 varieties of Anopheles mosquitoes in East Pakistan.However, many of these species have not been found in Bangladesh and some of these records may have been mistakenly assisted to East Pakistan rather than West Pakistan.Ahmed (1987) summarizes 32 species and 2 varieties of Anopheles mosquitoes in Bangladesh but in our new list, we reported 36 species because An. turkhudi and An.nivipes were newly recorded (Jannat and Ahmed 2006;Alam et al. 2012, Bashar et al. 2012b).
We illustrated the distribution of 34 Anophelines species in Bangladesh maps .This is the first time in Bangladesh where distribution map of different Anopheles species are shown at district level while other researchers reported the distribution of their recorded species in tabular form only. Especially Covel (1927;1930), Christophers (1933) and Chowdhury et al. (2011) clearly described the density and distribution of Anophelines in Bangladesh in non-spatial formats.
As a pioneering work, this study reports complete distribution maps of Anopheles mosquitoes in Bangladesh.Our findings demonstrate that majority of the Anopheles species were found in Southeastern hilly parts of Bangladesh.However, An. vagus, An. philippinensis densely distributed all over Bangladesh.Potential malaria vectors, An. baimaii are completely confined within the hilly parts of the country.However, longitudinal entomological studies and vector surveillance are essential for better mapping of the Anopheles population.The complete distribution maps will be very helpful for government and private organizations to take specific control measures according to the location to reduce mosquito population as well as malaria in Bangladesh.

Figure 1 .
Figure 1.Sampling districts and malaria endemic areas in Bangladesh.

Table 1 .
List of the species of Anopheles found in Bangladesh.
*Denotes species collected and identified by the authors and preserved in the entomology laboratory of Jahangirnagar University.+ confirmed malaria vector in Bangladesh