Anopheles arabiensis in Sudan: a noticeable tolerance to urban polluted larval habitats associated with resistance to Temephos

Malaria Journal - Tập 17 - Trang 1-11 - 2018
Rasha S. Azrag1, Babiker H. Mohammed1,2
1Department of Zoology, Faculty of Science, University of Khartoum, Khartoum, Sudan
2Ministry of Health, Khartoum State, Malaria Control Department, Vector Surviellance Unit, Khartoum, Sudan

Tóm tắt

It has been documented that unplanned urbanization leads to the exposure of members of the Anopheles vectors to a range of water pollution in urban settings. Many surveys from African and Asian countries reported the presence of Anopheles larvae in polluted urban habitats. The present study documents an obvious tolerance of the melanic and normal forms of Anopheles arabiensis to urban polluted larval habitats accompanied by resistance to Temephos larvicide. A cross-sectional survey was carried out to inspect apparently polluted An. arabiensis larval habitats during the hot dry season of 2015. Larval specimens were collected from only apparently polluted habitats after visual inspection from 5 localities in Khartoum State. After morphological and molecular identification of random samples of larvae the magnitude of water pollution was determined using nine abiotic factors. The susceptibility status of An. arabiensis larval forms from normal and polluted habitats to Temephos was tested using the WHO standard diagnostic concentration doses. Morphological and PCR analysis of anopheline larvae revealed the presence of An. arabiensis, a member of the Anopheles gambiae complex. Seven out of 9 physiochemical parameters showed higher concentrations in polluted larval habitats in comparison to control site. Anopheles arabiensis larvae were found in water bodies characterized by high mean of conductivity (1857.8 ± 443.3 uS/cm), turbidity (189.4 ± 69.1 NTU) and nitrate (19.7 ± 16.7 mg/l). The range of mortality rates of An. arabiensis larvae collected from polluted habitats in comparison to An. arabiensis larvae collected from non-polluted habitats was 6.7–64% (LD50 = 1.682) and 67.6–96% (LD50 = 0.806), respectively. The present study reveals that minor populations of An. arabiensis larval forms are adapted to breed in polluted urban habitats, which further influenced susceptibility to Temephos, especially for the melanic larval forms. This could have further implications on the biology of the malaria vector and on the transmission and epidemiology of urban malaria in Sudan.

Tài liệu tham khảo

Awolola TS, Oduola AO, Obansa JB, Chukwurar NJ, Unyimadu JP. Anopheles gambiae s.s. breeding in polluted water bodies in urban Lagos, southwestern Nigeria. J Vector Borne Dis. 2007;44:241–4.

Kabula BI, Attah PK, Wilson MD, Boakye DA. Characterization of Anopheles gambiae s.l. and insecticide resistance profile relative to physicochemical properties of breeding habitats within Accra Metropolis, Ghana. Tanzan J Health Res. 2011;13:163–87.

Antonio-Nkondjio C, Fossog BT, Ndo C, Djantio BM, Togouet SZ, Awono-Ambene P, et al. Anopheles gambiae distribution and insecticide resistance in the cities of Douala and Yaoundé (Cameroon): influence of urban agriculture and pollution. Malar J. 2011;10:154.

Mukhtar M, Herrel N, Amerasinghe FP, Ensink J, Van Der Hoek W, Konradsen F. Role of wastewater irrigation in mosquito breeding in south Punjab, Pakistan. Southeast Asian J Trop Med Public Health. 2003;34:72–80.

Gunathilaka N, Karunaraj P. Identification of sibling species status of Anopheles culicifacies breeding in polluted water bodies in Trincomalee district of Sri Lanka. Malar J. 2015;14:214.

Tene Fossog B, Kopya E, Ndo C, Menze-Djantio B, Costantini C, Njiokou F, et al. Water quality and Anopheles gambiae larval tolerance to pyrethroids in the cities of Douala and Yaoundé (Cameroon). J Trop. Med. 2012;2012:429817.

Sattler MA, Mtasiwa D, Kiama M, Premji Z, Tanner M, Killeen GF, et al. Habitat characterization and spatial distribution of Anopheles sp. mosquito larvae in Dar es Salaam (Tanzania) during an extended dry period. Malar J. 2005;4:4.

El Sayed BB, Arnot DE, Mukhtar MM, Baraka OZ, Dafalla AA, Elnaiem DEA, et al. A study of the urban malaria transmission problem in Khartoum. Acta Trop. 2000;75:163–71.

Eltayeb GE. Urban slums reports: the case of Khartoum, Sudan. In: Understanding slums: Case studies for the global report on human settelments. London UCL, DPU, UN Habitat. 2003; p 20.

The Sudan population and housing census. 2008. ILO microdata repository.

WHO. Malaria entomology and vector control: part 1: learner’s guide. Geneva: WHO/CDS/CP; 2003. p. 69.

Gillies M, Coetzee M. A supplement to the anophelinae of Africa South of the Sahara. Publ South African Inst Med Res. 1987;55:63.

Scott JA, Brogdon WG, Collins FH. Identification of single specimens of the Anopheles gambiae complex by the polymerase chain reaction. Am J Trop Med Hyg. 1993;49:520–9.

Aboud M, Makhawi A, Verardi A, Raba’a F, Elnaiem D, Townson H. A genotypically distinct, melanic variant of Anopheles arabiensis in Sudan is associated with arid environments. Malar J. 2014;13:492.

WHO. Global plan for insecticide resistance management in malaria vectors (GPIRM). WHO/HTM/GMP/2012–5; Geneva: World Health Organization.

Finney DJ. Probit analysis: a statistical treatment of the sigmoid response curve. Oxford: Macmillan; 1947.

Trape JF, Lefebvre-Zante E, Legros F, Ndiaye G, Bouganali H, Druilhe P, et al. Vector density gradients and the epidemiology of urban malaria in Dakar, Senegal. Am J Trop Med Hyg. 1992;47:181–9.

Keiser J, Utzinger J, Caldas De Castro M, Smith TA, Tanner M, Singer BH. Urbanization in sub-Saharan Africa and implication for malaria control. Am J Trop Med Hyg. 2004;71:118–27.

Afrane YA, Klinkenberg E, Drechsel P, Owusu-Daaku K, Garms R, Kruppa T. Does irrigated urban agriculture influence the transmission of malaria in the city of Kumasi, Ghana? Acta Trop. 2004;89:125–34.

Elkhalifa SM, Mustafan IO, Wais M, Malik EM. Malaria control in an urban area: a success story from Khartoum, 1995–2004. Eastern Mediterr Health J. 2008;14:206–15.

Gimnig JE, Ombok M, Kamau L, Hawley WA. Characteristics of Larval Anopheline (Diptera: Culicidae) Habitats in Western Kenya. J Med Entomol. 2001;38:282–8.

Mutero CM, Ng’ang’a PN, Wekoyela P, Githure J, Konradsen F. Ammonium sulphate fertiliser increases larval populations of Anopheles arabiensis and culicine mosquitoes in rice fields. Acta Trop. 2004;89:187–92.

Fillinger U, Sonye G, Killeen GF, Knols BGJ, Becker N. The practical importance of permanent and semipermanent habitats for controlling aquatic stages of Anopheles gambiae sensu lato mosquitoes: operational observations from a rural town in western Kenya. Trop Med Int Health. 2004;9:1274–89.

Ndenga BA, Simbauni JA, Mbugi JP, Githeko AK. Physical, chemical and biological characteristics in habitats of high and low presence of Anopheline larvae in Western Kenya Highlands. PLoS ONE. 2012;7:e47975.

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Malaria Journal

Tập 17

1-11

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