STUDIES ON THE ABUNDANCE AND DISTRIBUTION OF MOSQUITOES AND PREVALENCE OF MALARIA IN YABO LOCAL GOVERNMENT AREA OF SOKOTO STATE NIGERIA
ABSTRACT
Study was conducted to determine the abundance and distribution of mosquitoes and the prevalence of malaria parasites in Yabo Local Government Area. Mosquito breeding sites identification employed the use of a digital camera to snap pictures of areas where mosquitoes were observed. Mosquitoes eggs, larvae, pupa were collected and identified using the dipping method while indoor mosquitoes were caught from rooms,/toilets between the hours of 8 – 10pm using insecticide spray. A total of 370 blood samples were collected, analyzed using thick/thin films and stained using standard procedures. Twelve different mosquitoes breeding sites were identified. A total of 5,425 adult mosquitoes were caught, out of which 3,546 (65.36 %) were indoors and 1,879 (34.64%) caught outdoors. Statistical analysis conducted indicated significant difference (p< 0.05) between the two collections. Mosquitoes encountered belong to three genera of Anopheles, Culex and Aedes. The most predominant genus was Culex with a total of 5,967 (99.48%) adult mosquitoes, while Anopheles were 28 (0.52%) adult mosquitoes caught. Out of 370 blood samples examined, 118 (31.9%) were positive for malaria. The only plasmodium species encountered was Plasmodium falciparum with Kilgori district having the highest positives 76 (20.5%). Results showed that malaria infection is significantly recorded (P<0.05) in females 87 (23.5%), those aged 1 -9 years 33 (8.9%), and month of August 66 (17.8 %). Considering the medical importance of mosquitoes and malaria, information provided from this study will serve as basis for understanding the implication of mosquitoes nuisance and mounting effective control strategies against the vector and the disease.
CHAPTER ONE
1.0 INTRODUCTION
Mosquitoes are insects belonging to the Phylum Arthropoda and Order Diptera. (Service, 1980; Cantwell, 2010). There are 3,100 known species of mosquitoes belonging to 35 genera which are further arranged into three sub-families. (Service, 1980). The distribution and population density of adult mosquitoes depend on a number of factors. These factors include, the behavioural patterns of the species, the prevailing climatic conditions of the area, the availability of breeding sites (i.e habitats) and food sources (Gilles and Warrel, 1993).
Mosquitoes are best known for their role in the transmission of diseases to man dependening on number of factors. Some of these factors are the vector potency of the arthropod in the replication of parasites within its body cavity as well as its ability to transmit the parasite to human during blood meal. Prevailing climatic conditions of the area as well as availability of breeding sites which enhances mosquitoes abilty to survive, breed and reproduce favourably (WHO, 2005a).
Among the more important diseases transmitted by mosquiroes are malaria, yellow fever, dengue fever, encephalitis and filariasis. Of these, malaria is by far the most important. Malaria accounts for nearly 110 million clinically diagnosed cases per year, 60% of outpatient visits and 30% hospitalizations, an estimated 300, 000 children die of malaria each year, and up to 11% of maternal mortality in Nigeria (WHO/UNICEF, 2013). In addition to the direct health impact of malaria, there is also a severe social and economic burden on the communities and country as a whole, with about N132 billion lost to malaria annually in form of treatment costs, prevention, loss of man hours etc. Nigeria (WHO/UNICEF, 2013). Malaria is especially a serious problem in Africa, where one in every five (20%) childhood deaths is due to the disease. An African child has an average year between 1-6 with atleast 4 – 5 episodes of malaria fever each, and every 30 seconds, a child dies from malaria. Globally, about 3.3 billion people, half of the world’s populations are at risk of malaria every year, this leads to about 250 million cases and nearly one million deaths. People living in the poorest countries are the most vulnerable (Erhabor et al., 2012). With the constantly changing environment, the epidemiology of mosquito-borne diseases is also modified. Global warming, periodic flooding and deforestation have opened new habitats to mosquitoes which show high plasticity in their breeding behaviour and readily spread their distribution. In fact, sporadic malaria outbreaks have been reported in non-endemic countries and transmission of the disease was caused by the bite of a locally infected Anopheles species (Zucker, 1996).
STUDIES ON THE ABUNDANCE AND DISTRIBUTION OF MOSQUITOES AND PREVALENCE OF MALARIA IN YABO LOCAL GOVERNMENT AREA OF SOKOTO STATE NIGERIA