Prevalence and distribution of human malarial infection in district Multan, Punjab, Pakistan

The present study was undertaken during 2015-17 with the objective to provide data of malarial infections in human population based on incidences in twenty different localities of district Multan, Punjab, Pakistan. The blood slides of suspected patients were studied to identify the malarial parasites. Slide positivity was found to be 1478 (39.20%) out of 3770 and Plasmodium vivax infection was 905 (61.23%), Plasmodium falciparum 425 (28.75%) and mixed species (P. vivax and P. falciparum) 148 (10.01%) were identified. In the month of December, 150 cases (73.25%) of P. vivax infection counted to be the highest, whereas, 42 cases (58.33%) of P. vivax in the month of September were recorded. The P. falciparum infection remained highest in the month of August with 58 cases (25.66%) and lowest in the month of May with 24 (23.76%). Similarly infection of mixed species remained highest 30 (13.27%) in August and lowest 7 (7.60%) in the month of February. Infection in male was highest 850 (57.51%) and female was lowest 628 (42.48%). No incidence of Plasmodium ovale and Plasmodium malariae infection was to be observed in this study. The results of present research work concluded that P. vivax and P. falciparum are serious health hazards which can ultimately lead to serious cerebral malaria problems. However, no association was found between age group, sex and type of infection. Therefore, it can be concluded that the incidence of any type of infection may happened from person to person of any age group and in any sex.


Introduction
Malaria is known as a major parasitic diseases in all over the world. Over 225 million malarial cases were reported in 2011. Species Plasmodium falciparum is the most severe form of malaria parasite. Mostly it is transmitted through the bite of an infected female mosquito known as Anopheles when it feeds on human beings [1]. Malaria is known as one of the most devastating disease throughout in the world and 4 billion people live under the threat of malaria in 25 endemic countries [2] and each year it kills over a million mostly children [3]. Malaria is considered as one of the major poverty disease and needs to be eradicated. Due to consequences of malaria, children below five years and pregnant women are felt hardest. With the lack of hygiene and proper nutrition, a child dies from malaria after every thirty seconds [4]. At CMH, Multan [5] 125 cases of Plasmodium falciparum malaria were studied to evaluate seasonal variations and modes of transmission. The incidence of Plasmodium falciparum remained high among troops during the months of August to November. In general population of district Buner, [6] studied prevalence of malaria and recorded highest rate of infection (11.71%) in the month of August while in March the lowest rate of infection (3.8%) was noted. In pediatric age group 250 cases of malaria were investigated by [7] who found high rate of infection of Plasmodium vivax (63.2%) as compared to infection of Plasmodium falciparum (35%). In Karachi including other areas of province Sindh, Malaria was studied by [8] it was observed that infection of Plasmodium vivax were more than two times higher than the infection of Plasmodium falciparum. In many districts of the province Sindh [9] fond that Plasmodium falciparum ratio was increasing day by day. In North West Frontier Province (NWFP) malaria was studied by [10] who observed cerebral malaria as more common infection in males and for pregnant females it was highly vulnerable. In another study [7] among the 165 cases of malarial parasite in children, 145 cases were diagnosed as Plasmodium vivax and 20 cases of Plasmodium falciparum. At Ayub Teaching Hospital Abbottabad the study regarding the pattern of malarial infection by [11] 1998 patients were screened and 150 (7.5%) were found to be infected by Plasmodium vivax in 72.2% and Plasmodium falciparum in 24.3% cases.
In Balochistan, cerebral malaria is declared as a major community problem. In a study [12] to observed epidemiology of cerebral malaria and its mortality in patients in Quetta City, 63% cases of cerebral malaria in children while 37% cases in adults were investigated. Furthermore, in a study of urban and rural areas of Quetta district [13,14] in 2003 and 2004 in the age group of 22 and above, higher rate of incidence of Plasmodium falciparum (17.8%, 16.4%, respectively) were noted. A recent report about malaria from Pakistan, which was published in 2017, evidence sustained decrease in the number of cases, but however we are unable to achieve the target in all over the world about malarial eradication [15]. Many studies have been conducted to investigate the knowledge, attitudes and practices of people with respect to malaria but only few to know the cause of malaria. Investigating the rate of prevalence of malarial parasites in human population of the Multan district was the objective of present study.

Materials and methods
Multan is located in the southern part of the province Punjab, Pakistan. Multan is known as an arid area with very hot summer and cold winters. In winter the average lowest temperature is 4.4 o C (40.1 0 F) while in summer the highest average temperature recorded is 42.2 0 C (108.1 0 F). Different localities of Multan district were studied during August 2015 to July 2017 and blood of human patients suffering from malaria was screened to record malarial parasite species. The patients were categorized into 5 different age groups: 1-10 years of age, 11-20 years, 21-30 years, 31-40 years and 41 years and above. Two different methods were adopted to detect malarial cases.
[16] A) PCD (Passive Case Detection) technique where blood films were taken from health stations from the patients with symptoms leading to malaria. B) ACD (Active Case Detection) where blood films are prepared and collected from the persons with symptoms and signs of malaria during home visits. The blood slides collected using the PCD and ACD [16] techniques were carried to laboratory where these slides were stained with the help of Giemsa's stain. From the keys furnished by [17] identification of species of parasites was made.

Results
A total 3770 blood smears were prepared from 5 age groups ranging from 1 year to 41 years and above from different localities of Multan District of Southern Punjab during August 2015 to July 2017. However, due to different localities with different hygienic conditions variations were observed throughout the district Multan. Out of 3770 cases studied, 1478 cases were found to be of Plasmodium positive counting to 39.02% of total population studied. Regarding species, Plasmodium vivax was observed to be the highest 905 (61.23%) as compared to that of Plasmodium falciparum 425 (28.75%) and mixed species (Plasmodium vivax and Plasmodium falciparum) 148 (10.01%) (

Discussion
In Pakistan, malaria is considered to be a continuous severe public health problem [18]. From the Eastern Mediterranean region in 2010, over one million malarial cases through microscopy confirmed were reported of which 25% came from Pakistan [1]. Approximately 325 million people affect through malaria and causes more than a million of deaths per year throughout the world. Plasmodium falciparum has high mortality as compared to other plasmodium and it causes several diseases such as algid malaria, renal failure and cerebral malaria [5]. This survey was conducted to provide up to date information about malarial prevalence throughout District Multan. In this analysis, samples were collected from patients suffering from malaria with symptoms and one limitation is the potential for district Multan region in accordance to treatment seeking behaviour and centres for access to treatment. But unfortunately prior to diagnosis information on treatments taken was not collected and could be included in this study. In addition to this, season variations were also to be noted in the district areas of Multan where the highest rate of infection of Plasmodium vivax in December, Plasmodium falciparum in August and mixed species (Plasmodium vivax and Plasmodium falciparum) in August. Despite this information, the data presented in this study is more comprehensive and shows current characterization of prevalence of malaria in Multan District than has previously been available. The prevalence of Plasmodium vivax was observed as highest (61.23%) as compared to that of Plasmodium falciparum (28.75%) and mixed species (Plasmodium vivax and Plasmodium falciparum) ( by [13, 14, 19-21, 27]. In another study in 33 different localities of Quetta (city) visited showed that P. vivax was found to be the most common species with the highest rate of frequency (84.53%) as compared to that of P. falciparum (6.02%) in children [28]. These results are similar with our findings. In this study, mixed infection of 8.2%, 7.69%, 7.28%, 9.15% and 14.93% was observed. Mixed infection on 2.4% was observed in Multan district by [25]. However, in Quetta district, the same 2.4% was observed [26]. During this study no case of Plasmodium ovale or Plasmodium malariae infection was to be observed and the same were the observations of [25] in District Multan.

Conclusion
Pakistan is facing several challenges in the control and management of malaria including lack of diagnostic facilities, misdiagnosis and use of presumptive treatments. The results of this study indicate that Plasmodium infection in Pakistan are largely attributed to Plasmodium vivax but Plasmodium falciparum and mixed species of Plasmodium infections are also prevalent. In addition to this, regional variation in the prevalence and species composition of malaria is very high. So, malaria control efforts should be focused where malaria prevalence is highest with emphasis on improving species diagnosis. Authors' contributions