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Mosquito breeding ground in Port Harcourt River Basin University, Nigeria (Diptera: mosquito family)

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https://www.eduzhai.net Public Health Research 2020, 10(4): 119-122 DOI: 10.5923/j.phr.20201004.02 Breeding Sites of Mosquitoes (Diptera: Culicidae) at the University of Port Harcourt, Rivers State, Nigeria Noutcha M. A. E., Nwokedike V. O., Asadu P. C., Okiwelu S. N.* Entomology and Pest Management Unit, Department of Animal and Environmental Biology, University of Port Harcourt, Port Harcourt, Rivers State, Nigeria Abstract Malaria is the most widespread parasitic disease in the inter-tropics, especially in Sub-Saharan Africa. Lymphatic filariasis is a major cause of acute and chronic morbidity, affecting humans in tropical and sub-tropical countries. Both diseases involve culicid vectors. Integrated Vector Management (IVM) consists of use of insecticide treated nets (LLINTs), Indoor Residual Spray (IRS) and larviciding. A prerequisite to effective larviciding is an accurate knowledge of breeding sites. Breeding sites at two parks at the University of Port Harcourt were identified over a 2-month period; standard keys were used for immature and adult mosquito identifications. Mosquitoes utilized both containers and pool breeding site-types. Based on number of breeding site, the highest numbers were from tyres, puddle and plastic containers; lowest number per breeding site was from tin cans. However, these differences were not significant. More immatures were collected from University Park, the larger of the 2 parks, but the difference was not significant. In University Park, Aedes was the most abundant while Anopheles was least. In Delta Park, Anopheles was highest and Culex least. The differences were not significant. The varying choices of breeding sites across localities by species in the 3 genera (Aedes, Anopheles, Culex) highlighted the need for detailed investigations on preferred breeding sites at each location, prior to larviciding. Keywords Aedes, Anopheles, Culex, Breeding sites, University, Rainforest, Nigeria 1. Introduction Malaria is the most widespread parasitic disease in the inter-tropics, especially in Sub-Saharan Africa [1]. According to the WHO, malaria affected 228 million worldwide in 2019, compared to 219 million in 2017, with 405,000 human losses [2]. Among the deaths attributable to malaria, 67% were children under the age of 5years [2]. In addition, Africa remains the continent most affected by the disease with 93% of malaria episodes and 74% of deaths [2]. While has been reduction in the malaria burden in a few countries, challenges of pyrethroid resistance and the need to target outdoor transmission make integrated vector management an appealing approach [3]. It is estimated that globally 1.2 billion people are at risk to lymphatic filariasis (Lf), a major cause of acute and chronic morbidity, affecting humans in tropical and subtropical countries [4]. There are 3530 species of mosquitoes in 43 genera of the family Culicidae. They are divided into 3 subfamilies: Anophelinae (Anophelines), Culicinae (Culicines) and Toxorhynchitinae. The most important vector species belong to the genera: Anopheles, Culex, Aedes [5]. Human Malaria is caused by * Corresponding author: okiwelu2003@yahoo.com (Okiwelu S. N.) Received: Jul. 18, 2020; Accepted: Aug. 23, 2020; Published: Sep. 15, 2020 Published online at https://www.eduzhai.net Plasmodium parasites transmitted by female mosquitoes, Anopheles. In West Africa, the most efficient vector is the Anopheles gambiae complex (Anopheles gambiae s. l.). The important freshwater species are An. gambiae s.s., An. arabiensis and the salt water breeding species, An. melas in the swamps [6,7]. Bancroftian filariasis in West Africa is caused by Wuchereria bancrofti and transmitted by Anopheles spp. in rural and Culex quinquefasciatus in urban areas [8,9]. In West Africa, Aedes aegypti is the vector of the causative virus of yellow fever [10] and vector of the causative virus of dengue fever in East Africa [11]. Although there had been progress in filariasis control since the initiation of Mass Drug Administration (MDA) programmes, challenges have emerged [12]. These challenges have led to growing concern on the effectiveness of MDA; involving vector control is now thought to have great potential to become an important supplementary component of the filariasis elimination campaign. Similarly, an Integrated Vector Management (IVM) has been recommended for malaria control by the World Bank [13], consisting of Long Lasting Insecticide Treated Nets (LLITNs), Indoor Residual Spray (IRS) and larviciding. An important prerequisite to larviciding, is an accurate knowledge of the breeding sites of major diseases vectors. The increasing number of students attending the University Health Centre for malaria and records of lymphatic filariasis at the adjacent University of Port 120 Noutcha M. A. E. et al.: Breeding Sites of Mosquitoes (Diptera: Culicidae) at the University of Port Harcourt, Rivers State, Nigeria Harcourt Teaching Hospital (Pers. Comm.) are of grave concern. Furthermore, the absence of LLITNs in students’ hostels and the volume of human traffic make IRS untenable. Hence, the focus of the IVM is on larviciding and this requires an accurate knowledge of breeding sites, which necessitated this study. selected probable breeding sites. A 100ml-silver ladle and Pasteur pipettes were used for immature collections. Immatures were identified by standard keys [5,15]. Larvae were reared to adults and identified by standard keys [16,17]. ANOVA (t-test, Correlation coefficient) and Post Hoc Tests were used for statistical Analyses. 2. Materials and Methods Study Area The University of Port Harcourt is at the periphery of Port Harcourt metropolis, 4° 55′ 26 N and 6° 54′12 E, in lowland rain forest. There are two seasons: rainy (April-October) and dry (November-March). The heaviest precipitation is in September with an average rainfall of 367mm. December and January are usually the driest. Average temperature is 25-28°C [14]. The University consists of three parks: University (largest), Delta and Choba. Choba Park is gradually being converted to the commercial Park of the University and hence was not featured. Methods Collections of immatures were undertaken, 8.00-10.00hrs daily, 01 August- 30 September, 2018. Samples were collected weekly over a 6-week period from randomly 3. Results Mosquitoes utilized both container and pool breeding site-types. Based on number of immatures per breeding site, the highest numbers were in tyres (container-type), puddle (pool-type) and plastic container, in descending order (Table 1). The lowest number per breeding site was from tin can. However, these differences were not significant (t>0.5). There was association among the 6 breeding site-types, because correlation coefficients between them were greater than 0.50. More immatures were collected from University Park, the larger of the 2 parks. It also had more breeding sites. However, the difference was not significant (p>0.05). In Delta Park, the highest number was the genus Anopheles, while Culex was least. In University Park, the highest number was the genus Aedes, while Anopheles was least (Table 2). These differences were significant (p>0.05). Table 1. Numbers of mosquito immatures per breeding site-types Category Site-type Breeding site-type Tyre Plastic Containers Tin Can Drum Sub-total Pools Gutter Puddle Sub-total Total Number of breeding sites examined 6 18 15 3 42 15 8 23 65 Number of immatures collected 93 202 80 20 395 102 105 207 602 Number of immatures per breeding site 15.50 11.22 5.33 6.67 9.40 6.80 13.13 9.00 Table 2. Relative Abundance of Mosquito Immatures from the different Parks Location Site Delta Park Unipark Sub-total Aedes Spp. No (%) 84 (33.33) 149 (42.57) 233 (38.7) Anopheles Spp. No (%) 98 (38.89) 99 (28.28) 197 (32.72) Culex Spp. No (%) 70 (27.78) 102 (29.14) 172 (28.57) Total No (%) 252 (41.86) 350 (58.14) 602 (100.00) 4. Discussion Breeding sites of Culicidae were varied; diverse sites had also been recorded in other studies. Culex immatures had also been recorded from tyres, plastic and metal containers, pools [10,18,19,20]. Other studies recorded pit latrines as preferred breeding site types of Culex [9,19]. Anopheles immatures from containers (tyres, metal and plastic), borrow pit, hoof prints and pools had been reported [10,20,21,22]. Among container site-types, Rabiu and Ahmed [10] found discarded tyres most preferred at Ilorin, while Okorie [23] recorded container breeding site-types as least preferred at Ibadan, Nigeria. Aedes immatures were collected from containers (tyres, metal, plastic, pot) and pools, which conformed to results from earlier studies [10,20,24]. The diversity in breeding site-types from these results and those Public Health Research 2020, 10(4): 119-122 121 of the referenced studies, highlight the necessity for a thorough investigation of preferred breeding sites at each location, prior to larviciding. The high numbers of Anopheles, Culex, Aedes emphasize the need for integrated vector management, with specific focus on larviciding at the University, since species in these genera are vectors of the causative organisms of malaria, lymphatic filariasis and yellow fever [9,18,24]. The absence of a yellow fever epidemic in the area in the past decades could be attributed to the absence of the causative virus, although Mona monkeys (Cercopithecus mona) have been recorded in the area over the past 2 decades [24,25,26,27]. [10] Rabiu H. A., Ahmed A. 2018. A preliminary study on the abundance and species composition of mosquitoes breeding in discarded automobile tyres in Minna, Niger State, Nigeria. International Journal of Mosquito research 6: 119-123. [11] Ngugi HN., Mutuku FM., Ndenga BA., Aswani P., Irungu LN, Mukoko D., Vulule J., Kitron U., Labeaud AD. 2017. Characterization and productivity profiles of Aedes aegypti (L.) breeding habitats across rural and urban landscape in western and coastal Kenya. Parasites and Vectors 10: 331343. [12] Hotez P., Raff S., Fenwick A., Richards F Jr., Molyneux DH. 2007. Recent progress in integrated neglected tropical diseases control. Trends in Parasitology 23: 511-514. 5. Conclusions The varying choices of breeding sites across locations highlight the need for detailed investigations at each locality to identify preferred sites prior to effective larviciding. The high numbers of immatures recorded in these studies stress the need for urgency in larviciding to reduce the incidence of malaria and lymphatic filariasis in the University. [13] Barat LM. 2006. Four malaria success stories: how malaria burden was successfully reduced in Brazil, Eritrea, India and Vietnam. American Journal of Tropical Medicine 74: 12-16. [14] Wikipedia (August 15, 2018) Retrieved September 25, 2018, from the free encyclopedia [15] Mullen GR. and Durden L. A. (Eds) 2009. Medical and Veterinary Entomology, 2nd Edition. Academic Press. 637pp. [16] Gillett JD. 1972. Common African mosquitoes and their medical importance. 106pp. William Heineman. Medical Books. London. REFERENCES [1] World Health Organization 2018. The World Malaria Report 2018. WHO, Geneva. Pp.1-210. [2] World Health Organization 2019. The World Malaria Report 2019. WHO, Geneva. Pp.1-232. [3] Cotter C., Sturrock HJ., Hsiang MS., Liu J., Philips AA., Hwang J., Feachem B. 2013. The changing epidemiology of malaria elimination. New Strategies for challenges. Lancet. 382: 900-911. [4] Michael E., Bundy DAP. 1997 Global mapping of lymphatic filariasis. Parasitology Today. 11: 472-476. [5] Service M. 2012. Medical Entomology for students. Cambridge University Press. 5th Edition. 289. [6] Ebenezer A., Noutcha M.A.E., Okiwelu S.N., Commander T. 2014. Spatial distribution of the sibling species of Anopheles gambiae sensu lato (Diptera: Culicidae) and malaria prevalence in Bayelsa State, Nigeria. Parasites and Vectors 7: 1-6. [7] Olalubi O. A., Chinwe G.R. 2016. Promoting larval source managenment as a vital supplemental addendum and more likely cost-effective approach for malaria vector control in Nigeria. Journal of Prevention and Infection control 2: 15-20 6. [8] Bockarie M.J., Pedersen E.M., White G.B., Michael E. 2009. Role of vector control in the global programme to eliminate lymphatic filariasis. Annual Review of Entomology 54: 467487. [9] Itina V.I., Noutcha M.A.E., Okiwelu S.N. 2014. Breeding Sites of Culicidae in Akwa Ibom State, Nigeria. Public Health Research 4: 768-773. [17] Louis F. 2003. Une clé d’identification de l’Anopheles. L’aile. http://asmt. Louis.free.fr/. [18] Okiwelu S. N., Noutcha M. A. E. 2012. Breeding sites of Culex quinquefasciatus (Say) during the Rainy Season in Rural Lowland Rainforest, Rivers State, Nigeria. Public Health Research 2: 64-68. [19] Emidi B., Kisinza W. N., Stanley G. Mosha F. W. 2017. Seasonal variation of Culex quinquefasciatus densities emerged from pit latrines in rural settings, Moheza, Tanzenia. S. M. Journal of Public Health and Epidermiology 3: 1040-1045. [20] Pamba R., Kombo AA., Zinga-Koumba CR., Sevidzem SL., Mbouloungou A., Yacka LL., Djegbenou LS, Mavoungou JF, Batchi BM. 2020. Typology of breeding sites and species diversity of Culicids (Diptera: Culicidae) in Akadan and environs (North West, Gabon). European Journal of Biology and Biotechnology 1: 1-6. [21] Noutcha M. A. E., Okiwelu S. N. 2013. Breeding Sites of Anopheles gambiae S. E. (Gilles) in Rural lowland rainforest, Rivers State, Nigeria. Public Health Research 3: 50-53. [22] Getachew D., Balkew M., Tekie H. 2020. Anopheles larval species composition and characterization of breeding habitats in two localities in the Ghibe River Basin, South Western Ethiopia. Malaria Journal 19: 65-78. [23] Okorie T.G. 1978. The breeding site preference of mosquitoes at Ibadan, Nigerian Journal of Entomology 3: 71-80. [24] Okiwelu SN, Ewurum N, NOUTCHA MAE. 2008. “Wildlife Harvesting and Bushmeat Trade in Rivers State, Nigeria: - I - Species Composition, Seasonal Abundance and Cost”. Scientia Africana, 7(1): 1-8. [25] Okiwelu SN, Akpan-Nnah PM, NOUTCHA MAE, Njoku CC. 2010. Wildlife Harvesting and Bushmeat Trade in Rivers State, Nigeria II: Resilience of the Greater Cane Rat, 122 Noutcha M. A. E. et al.: Breeding Sites of Mosquitoes (Diptera: Culicidae) at the University of Port Harcourt, Rivers State, Nigeria Thryonomys swinderianus (Rodentia: Thryonomidae). Scientia Africana 9 (2): 18-23. [26] Noutcha MAE., Nzeako SO., Okiwelu SN. 2017. “Offtake Numbers at 5-Yearly Intervals over a 10 Year- Period in the Catchment Area of a Rural Bushmeat Market, Rivers State, Nigeria”. Journal of Scientific Research and Reports 13(3): 1-5. [27] Noutcha M. A. E., Amadi U. H., Okiwelu S. N. 2020. Wildlife harvesting and bushmeat trade in Rivers State, Nigeria-IV- The resilience of the African civet, Civettictis civetta (Carnivora: Viverridae) and records of rare species Journal of Ecology and The Natural Environment(in press). Copyright © 2020 The Author(s). Published by Scientific & Academic Publishing This work is licensed under the Creative Commons Attribution International License (CC BY). http://creativecommons.org/licenses/by/4.0/

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