Prevalence of malaria from peripheral blood smears examination: A 1-year retrospective study from the Serbo Health Center, Kersa Woreda, Ethiopia

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1 Journal of Infection and Public Health (2009) 2, Prevalence of malaria from peripheral blood smears examination: A 1-year retrospective study from the Serbo Health Center, Kersa Woreda, Ethiopia Kaliyaperumal Karunamoorthi a,b,, Mammo Bekele a a Unit of Vector Biology & Control, Department of Environmental Health Science, College of Public Health and Medical Sciences, Jimma University, Jimma, Ethiopia b Research and Development Center, Bharathiar University, Coimbatore, Tamil Nadu, India Received 9 May 2009; received in revised form 27 July 2009; accepted 27 August 2009 KEYWORDS Malaria; Retrospective study; Blood film examination; Kersa Woreda; Ethiopia Summary Malaria is a major public health problem in Ethiopia. Over the past years, the disease has been consistently reported as the first leading cause of outpatient visits, hospitalization and death in health facilities across the country. Thus, a retrospective study was conducted to determine the prevalence of malaria from peripheral blood smear examination from the Serbo Health Center of Ethiopia. The case notes of all malaria cases treated between July 2007 and June 2008 were carefully reviewed and analyzed. Of the total 6863 smears, 3009 were found to be positive and contribute 43.8% of diagnostic yield. Plasmodium falciparum constituted the most predominant [64.6% (1946/3009 cases)], while Plasmodium vivax confirmed with 34.9% (1052/3009) cases. Among patients who underwent diagnostic testing and treatment for malaria, males [63.8% (1918/3009 cases)] were more prone to have a positive malaria smear than females [36.2% (1091/3009 cases)]. Chi-square statistical analysis shown that there was a statistically significant association found between male cases and number of positive blood smear ( 2 = 28.1; df = 7; p-value = 0.001). The present study results clearly suggest that the catchment area of Serbo Health Center is prone for epidemic malaria and the situation is quite deteriorating. At the moment, although we are not equipped with magic bullet for malaria effective low-cost strategies are available for its treatment, prevention, and control. Therefore, creating awareness by active health education campaigns and applying integrated malaria control strategy could bring the constructive outcome in the near future King Saud Bin Abdulaziz University for Health Sciences. Published by Elsevier Ltd. All rights reserved. Corresponding author at: Unit of Vector Biology & Control, Department of Environmental Health Science, College of Public Health and Medical Sciences, Jimma University, Jimma, Ethiopia. Tel.: ; fax: address: k karunamoorthi@yahoo.com (K. Karunamoorthi) /$ see front matter 2009 King Saud Bin Abdulaziz University for Health Sciences. Published by Elsevier Ltd. All rights reserved. doi: /j.jiph

2 172 K. Karunamoorthi, M. Bekele Introduction Malaria afflicts 90 countries and territories in the tropical and subtropical regions and almost one half of them are in Africa, South of Sahara. About 36% of the world population (i.e., 2020 million) is exposed to the risk of contracting malaria. The World Health Organization estimates million malaria cases annually, with 90% of this burden being in Africa. In addition, the estimated annual mortality attributed to malaria ranges from 700,000 to 2.7 million globally and >75% of them are African children and expectant mothers. Doubts have been expressed about reliability of these estimates because most of the hyper and holoendemic countries, especially in Africa, lack credible diagnostic facilities and reporting systems [1,2]. Malaria is a major public health problem in Ethiopia. The diverse eco-climatic condition in the country makes the malaria transmission pattern seasonal and unstable usually characterized by frequent focal and cyclic widespread epidemics [3]. In Ethiopia, malaria was reported to be endemic first and foremost by the Italian and British scientists from the mid-1930s to the late 1950s. In 1953, severe outbreaks that devastated the lives of 7000 people was reported to occur in Dembia plain near Lake Tana [4] and more than 1 million cases were recorded in the recent epidemic year of 1998 [5]. In 2003 and 2004, there were serious malaria epidemics throughout the country, which affected 15 million persons in 3 federal regions [6]. An estimated 68% (50 million people) of the population lives in areas at risk of malaria. Malaria was reported as the primary cause of health problems in accounting for 17% of outpatient visits, 15% of hospital admissions and 29% of inpatient deaths [7]. The main components of the malaria control approach in Ethiopia include diagnosis and treatment of cases, the application of selective vector control measures and strengthening the information system to facilitate the prevention, early detection and control of epidemics [8]. Currently, about 6 10% of the world population harbor malaria parasites in their bloodstream [9]. Especially, the physical consequences of infection with Plasmodium falciparum are the main causes of malaria morbidity and mortality in Africa [10]. Almost 3% of disability adjusted life years (DALYs) are due to malaria mortality globally [1]. Because of its dependence on human/vector (mosquito) contact, malaria is considered to be a disease of poverty. Underprivileged people in the rural endemic area become infected with malaria. Also it causes economical lost and impact on the social functions. Monitoring of the incidence of the disease can provide useful data for disease surveillance and control [11]. Health facility records are important sources of malaria data, because they are readily available, can provide useful indicators on the situation of malaria at a lower cost. They are useful not only for planning malaria control and evaluating the impact of health services, but also for epidemiological surveillance. If properly utilized, this information will urge the decision makers to act timely to intensify malaria control interventions effectively and efficiently [12]. Indeed, malaria imposes enormous socioeconomic burden on humankind. Malaria remains a major public health problem which contributes to poverty and underdevelopment in sub-saharan Africa particularly in country like Ethiopia. Currently, information regarding gender and age wise prevalence of malaria is quite inadequate in Ethiopia. Therefore, the purpose of the present investigation was to determine the prevalence of malaria from peripheral blood smear examination from the Serbo Health Center, Kersa Woreda an endemic area of Ethiopia. The present study outcome could serve as valuable resource for malaria surveillance and control strategy in the near future. Materials and methods Study setting The setting is the Serbo Health Center located in Serbo town, Kersa Woreda an malaria endemic area of Ethiopia. Kersa is 1 of the 180 Woredas in the Oromia Region of Ethiopia. The altitude of this Woreda ranges from 1740 to 2660 m above sea level. Woreda is an administrative division of Ethiopia (managed by a local government), equivalent to a district. Kersa Woreda is consists of 31 Kebeles, which are the smallest unit of local government in Ethiopia. Based on figures published by the Central Statistical Agency [7] in 2005, this Woreda has an estimated total population of 329,629, of whom 162,690 were males and 166,939 were females. Malaria is a leading cause of morbidity and mortality in the Kersa Woreda. According to malaria stratification of the Kersa Woreda, 20 Kebeles are in high risk of malaria, 3 Kebeles are in the medium risk of malaria, 6 Kebeles are low risk of malaria transmission and just only 2 Kebeles are free of malaria. Each Kebele is divided into many tiny hamlets, each with huts. Commonly the males of this region are out in the city due to employment, education and other activities. However, women, children and geriatric population stay back in the

3 Prevalence of malaria from peripheral blood smears examination 173 villages. This results in constant inflow and outflow of population, which might be leading to spread of malaria in both directions. Kersa Woreda has 1 health center, 3 health stations, 10 health posts and 24 Kebeles are covered by the health extension workers. However, laboratory based medical treatment services accessible at the health center only. Serbo Health Center has four laboratory technicians to perform malaria diagnosis. The blood films were taken from all febrile patients presenting themselves to a health center with symptoms of shivering and fever or a history suggestive to malaria. Thick and thin blood film slides were prepared using 10% Giemsa solution for 30 min. The stained slides were examined under a light microscope using 100 oil immersion by an experienced laboratory technician. Parasitaemia was calculated per 200 white blood cells (WBC) assuming 8000 WBC/ l of blood [13]. Generally, if the patients did not have malaria, the physician advice the patient for other diagnostic test for other diseases excluding malaria or refer to other higher health care facilities. However, Due to remoteness and economic constraints many febrile cases might have not reported to health center. Such malaria cases possibly might have received the treatment either from health extension workers or self-medication and they were not included. It was the major limitation of this current investigation. Data extraction Concerning the data extraction, the case notes of all malaria cases admitted between July 2007 and June 2008 to the Serbo Health Center of Kersa Woreda, were reviewed and carefully analyzed. The demographic data collected from the database included sex and age of all study subjects. Statistical analysis Statistical analysis was carried out using SPSS, version 12 statistical software packages. Range and mean were analyzed and appropriate tables, graphs and percentage were displayed. Level of significance also determined by using 95% of confidence intervals and p-value. Results A total of 6863 blood smear was examined for the detection of malarial parasites during the study period. The overall prevalence of Plasmodium slide Table 1 Gender and age wise detection of malaria parasites from blood smear examination between July 2007 and June 2008 from the Serbo Health Center, Kersa Woreda in an endemic area of Ethiopia. No. of blood film ve No. of blood film +ve Female cases Male cases p-value Total no. of blood film examined Age group (years) P. vivax P. falciparum Mixed infection Mixed infection Plasmodium falciparum Frequency % Frequency % Plasmodium vivax = df = p = * Total * p < 0.05 statistically significant.

4 174 K. Karunamoorthi, M. Bekele Distribution of malaria by species in percent- Figure 1 age. diagnostic yield was 43.8% (3009/6863), wherein P. falciparum was observed to be highest [64.6% (1946/3009 cases)] as compared with that of Plasmodium vivax 34.9% (1052/3009). During the study period, no case of Plasmodium malariae or Plasmodium ovale infection was observed. However, mixed infection with P. vivax and P. falciparum was identified (Table 1 and Fig. 1). Among patients who underwent diagnostic testing for malaria, males [63.8% (1918/3009 cases)] were more prone to have a positive malaria smear than females [36.2% (1091/3009 cases)]. Chi-square statistical analysis clearly revealed that there was a statistically significant association found between male cases and number of positive blood smear ( 2 = 28.1; df =7;p-value = 0.001). The most affected age group was years [56.7% (378/667 cases)] (Table 1 and Fig. 2). Two hundred and twenty-eight patients admitted and treated as inpatients and rest of them were treated as outpatients. 74.5% (170 malaria admission/228 total admission) of inpatients were received treatment for malaria. Discussions Malaria has accompanied humankind since antediluvian period. Modern humans, Homo sapiens, began to emerge in Africa approximately 200,000 years ago [14,15] and developed during a period overlapping with the current genetic form of P. falciparum [16]. Humans first emigrated out of Africa between 100,000 and 40,000 years ago to colonize Asia, Europe, and Oceania [17]. The four species of malaria that infect humans today (P. vivax, P. ovale, P. malariae, and P. falciparum) arose from an ancestral form 200 million years ago [18]. Malaria is the largest single component of disease burden; epidemic malaria in particular, remains a major public health concern in tropical countries. In many developing countries, and especially in Africa, malaria exacts an enormous toll in lives, in medical costs, and in days of labor lost [19]. The present study chi-square test result revealed that there was a significant association between male patients and number of positive blood smears smear ( 2 = 28.1; df =7;p-value = 0.001). This could be explained by the fact that males are more active outdoors during early evening hrs than females. The present study results are similar reported by Jamaiah et al. [20]. The least affected age group was years (39.9%). This might possibly in this part of the world the elderly population mostly stay back in the villages besides their outdoor activities are relatively restricted than young male individuals. Thus, contract with malarial infection is reasonably minimal. The majority of cases occurred between the age group years age group (56.7%) followed by years age group (48.1%). The finding of this study similar with a study conducted in Malaysia that the majority of cases found between the age group years (43%) [21]. This could be because this age group people are the bread winners as a result they spend outdoors in the evening when peak biting activities of malaria vector mosquitoes are high than other age group individuals. Besides, they prefer to offer any available personal protec- Figure 2 Prevalence of malaria by age and gender between July 2007 and June 2008 from the Serbo Health Center, Kersa Woreda in an endemic area of Ethiopia.

5 Prevalence of malaria from peripheral blood smears examination 175 tion materials in particular bed nets to their family members mainly for children s and pregnant women rather than their own personal use. In the present study P. falciparum constituted the most predominant [64.6% (1946/3009 cases)], while P. vivax confirmed with 34.9% (1052/3009) cases. The findings were relatively comparable with earlier reports, which were found that infections with P. falciparum (>60%) and P. vivax (about 40%) have been consistently reported in many parts of the Ethiopia [22,23]. Another study which was carried out in the same study area found that the two most important causes of malaria were P. falciparum and P. vivax, comprising of 51.5% and 32.3% of the case, respectively [12]. Ethiopia has the highest proportion of P. vivax malaria on the continent, accounting for approximately 40% of all infection in the country [24]. Similarly few earlier studies also reported regarding high incidence of vivax malaria in Ethiopia, Yewhalaw et al. [25] reported that the predominant species was P. vivax followed by P. falciparum. Similarly, in central Ethiopia, Woyessa et al. [26] reported the predominance of P. falciparum during October while P. vivax tends to dominate during November. It is interesting to note that the dominant malaria in Africa is caused by P. falciparum, accounting for nearly 100% of malaria cases in most of the sub-saharan countries. This phenomenon is currently explained by the lack of Duffy receptors on the erythrocytes of Africans, which makes them resistant to infection by P. vivax, the more common species in the rest of the world [27]. Ethiopia is an exception in this respect, since it is a meeting place between Semitic and African races, and 25 35% of malaria cases in Ethiopia are due to P. vivax [28,29]. In the present study no case of P. malariae or P. ovale infection was observed. In addition, 0.5% of mixed malarial infection of both P. falciparum and P. vivax were also identified. A similar result was reported in a previous study [26]. It is estimated that there are million clinical cases of malaria each year worldwide; infection with P. vivax accounts for about 25% of these cases and infection with P. falciparum primarily accounts for the rest. There are million deaths attributable to malaria each year. Most of these deaths occur in African children and are caused by P. falciparum infections [1,2]. are major victims for this malicious and merciless killer. Malaria is a leading cause of morbidity and mortality in Ethiopia. Besides, it s a one of major obstacle to socio-economic development as the main transmission periods coincide with peak agricultural and harvesting period. The present study results clearly revealed that the catchment area of Serbo Health Center is extremely prone to epidemic malaria and the situation is quite deteriorating. Recommendation Currently, although we are not equipped with magic bullet for malaria, effective low-cost strategies are available for its treatment, prevention, and control. Therefore, active health education campaign should be instigated among the underprivileged section of the society about importance of regular deployment of insecticide-treated nets (ITNs), malaria treatment, prevention, and control in order to reduce the intolerable burden of malaria. In addition, introduction of integrated malaria vector control strategy in the catchment area of Serbo Health Center could bring the constructive outcome in the near future. Conflict of interest Funding: The authors would like to acknowledge Jimma University Student Research Programme (SRP) for pursuing this research work by providing fund. Competing interests: None declared. Ethical approval: Not required. Acknowledgements The authors wish to thank all staff members of Serbo Health Center, Kersa Woreda, Ethiopia for their timely help and support who assisted in retrieving the case notes to carry out this research work. Our last but not least heartfelt thanks go to our colleagues, School of Environmental Health Science, Faculty of Public Health, Jimma University, Jimma, Ethiopia, for their kind support and cooperation. Conclusions Indeed, malaria is frequently referred to as a disease of the poverty. Evidently, poorest countries of the world, in particular those in sub-saharan Africa References [1] Breman JG. The ears of the hippopotamus: manifestations, determinants and estimation of the malaria burden. Am J Trop Med Hyg 2001;64(1):1 11.

6 176 K. Karunamoorthi, M. Bekele [2] Snow RW, Guerra CA, Noor AM, Myint HY, Hay SI. The global distribution of clinical episodes of Plasmodium falciparum malaria. Nature 2005;434: [3] Federal Ministry of Health. National five years strategic plan for malaria control in Ethiopia: Addis Ababa: Malaria and Other Vector-borne Diseases Prevention and Control Team, Diseases Prevention and Control Department, Ministry of Health; [4] Covell G. Malaria in Ethiopia. J Trop Med Hyg 1957;60:7 16. [5] WHO-UNICEF. The Africa malaria report Geneva: Word Health Organization; [6] World malaria report Roll Back Malaria, World Health Organization and UNICEF. 294 pp. [7] CSA. The Ethiopian demographic and health survey Addis Ababa: Central Statistical Agency; [8] FMOH & UNICEF. Guide for program managers on the use of insecticide-treated nets in Ethiopia; July [9] Mayxay M, Pukrittayakamee S, Newton PN, White NJ. Mixed species malaria infections in human. Trends Parasitol 2004;20: [10] Snow RW, Craig M, Deichmann U, Marsh K. Estimating mortality, morbidity and disability due to malaria among Africa s non-pregnant population. Bull World Health Org 1999;77(8): [11] Phillips RS. Current status of malaria and potential for control. Clin Microbiol Rev 2001;14: [12] Deressa D, Chibsa S, Olana D. The distribution and magnitude of malaria in Oromia, Ethiopia. Ethiop J Health Dev 2004;18(3): [13] Cheesbourgh M. District laboratory practice in tropical countries, vol. II, 2nd ed. Noida: Gapsons Papers Ltd.; [14] Cann RL, Stoneking M, Wilson AC. Mitochondrial DNA and human evolution. Nature 1987;325:31 6. [15] The Y Chromosome Consortium. Anomenclature system for the tree of human Y-chromosomal binary haplogroups. Genome Res 2002;12: [16] Rich SM, Ayala FJ. The recent origin of allelic variation in antigenic determinants of Plasmodium falciparum. Genetics 1998;150: [17] Cavalli-Sforza LL, Feldman MW. The application of molecular genetic approaches to the study of human evolution. Nat Genet 2003;33: [18] Rich SM, Ayala FJ. Evolutionary origins of human malaria parasites. In: Dronamraju KR, Arese P, editors. Malaria: genetic and evolutionary aspects. New York: Springer; [19] Lambert PH. Malaria: past and present. org/medicine/educational/malaria; 2005 [accessed on April 24, 2009]. [20] Jamaiah I, Anuar AK, Najib NARN, Zurainee MN. Imported malaria: a retrospective study in University Hospital, Kuala Lumpur, a ten-year experience. Med J Malaysia 1998;53:6 9. [21] Jamaiah I, Rohela M, Nissapatorn V, Khoo BL, Khoo PS, Radhiyah M, et al. A 10-year ( ) retrospective study at University Malaya Medical Center (UMMC), Kuala Lumpur, Malaysia. Southeast Asian J Trop Med Public Health 2005;36(4):60 3. [22] Abeku TA, van Oortmarssen GJ, Borsboom G, devlas SJ, Habbema JDF. Spatial and temporal variations of malaria epidemic risk in Ethiopia: factors involved and implications. Acta Trop 2003;87: [23] Tulu AN. Malaria. In: Zein ZA, Kloos H, editors. The ecology of health and disease in Ethiopia, 2nd ed. Boulder, USA: West View Press; p Ministry of Health. National five-year strategic plan for malaria control in Ethiopia: Addis Ababa, Ethiopia: Malaria and Other Vector borne Diseases Prevention and Control Unit, Disease Prevention and Control Department; [24] Federal Ministry of Health. National five years strategic plan for malaria control in Ethiopia: Addis Ababa: Malaria and Other Vector-borne Diseases Prevention and Control Team, Diseases Prevention and Control Department, Ministry of Health; [25] Yewhalaw D, Legesse W, Van Bortel W, Gebre-Selassie S, Kloos5 H, Duchateau L, et al. Malaria and water resource development: the case of Gilgel-Gibe hydroelectric dam in Ethiopia. Malaria J 2009;8:21, doi: / [26] Woyessa A, Gebre-Michael T, Ali A. An indigenous malaria transmission in the outskirts of Addis Ababa Akaki Towen and its environs. Ethiop J Health Dev 2004;18:2 7. [27] Miller LH, Mason SJ, Clyde DF, McGinnis MH. The resistance factor to Plasmodium vivax in Blacks. N Engl J Med 1976;295: [28] Mathews HM, Armstrong JC. Duffy blood types and vivax malaria in Ethiopia. Am J Trop Med Hyg 1981;30: [29] Zein AZ, Kloos H. The ecology of health and disease in Ethiopia. Addis Ababa, Ethiopia: Ministry of Health; Available online at