Objective: To study the prevalence of malarial infections in human population of districts Loralai and Musakhel areas of Pakistan.
Methods: Malarial parasites were identified in the blood slides of suspected patients of the disease from July, 2004 to June, 2006, and encompassed 7899 subjects.
Results: Out of 7899 suspected cases of malaria, 2275 (28.8%) were found to be positive for malarial parasite in blood smear slides. Out of positive cases, 1633 (71.7%) were identified as Plasmodium falciparum infection, 642 (28.2%) cases with P. vivax. However, seasonal variation was also noted with the highest (83.9%:287/342) infection of P. falciparum in September and lowest (65.3 %: 34/52) in January in Loralai area whereas highest (76.9%:30/39) in October and lowest (3/9) in February in Musa Khel area. There was no case of Plasmodium malariae and P. ovale infection observed in the present study. These results are compared with those of other studies done in Pakistan.
Conclusion: The high prevalence rate (71.7 %:1633/2275) of P. falciparum poses a significant health hazard but 28.2% of P. vivax (642/2275) also may lead to serious complications like cerebral malaria. No association was found between types of infection and age groups (JPMA 59:132; 2009).
Malaria is one of the most devastating diseases in the World. Over 3 billion people live under the threat of malaria in 24 endemic countries1 and it kills over a million each year - majority being children.2
According to a conservative estimate, about 500,000 malaria cases occur per annum (About 40% of cases are due to Plasmodium falciparum which is significantly more common in the Sindh Province (64%).1 P. falciparum hasdeveloped resistance to chloroquin. The two main malaria vectors- An. culicifacies and An. stphensi are both resistant to organochlorines and the latter has also developed resistance to organophosphate (Malathion).3 In Pakistan, Akbar4 reported malaria at a children hospital Baqai Medical University and observed high incidence of falciparum as compared to vivax (65% vs 35%). Mohammad and Hussain5 studied prevalence of malaria in general population of district Buner and highest rate of infection (11.6%) was recorded in August while the lowest rate of infection (3.9%) was noted in March. Malaria inpediatric age group of 200 cases was investigated by Jamal et al6 and found high rate of P. vivax (62.5%) than P. falciparum.(36%). Malaria in Karachi and other areas in Sindh was studied by Mahmood7 who observed P. vivax to be two times higher than P. faciparum. Nizamani et al8 found that P. falciparum ratio was noted to be increasing in many districts of Sindh. Malaria in North West Frontier Province (NWFP) was studied by Iqbal et al9 and observed cerebral malaria more common in males and most vulnerable group was pregnant ladies. Jalal-ud-Din et al10 investigated malaria in children in Mansehra and observed 142 cases suffering from vivax and 12 from falciparum out of 160 cases. Idris et al11 while studying pattern of malarial infection at Ayub Teaching Hospital, Abbottabad found that out of 1994 patients screened, 145 (7.2%) were found infected. P. vivax was seen in the majority (72.4%) than P. falciparum (24.1%). In Balochistan too, cerebral malaria is a major community problem. Nawaz and Yasmin12 studied the prevalence of malaria in Afghan refugees settled in urban areas of district Quetta. Malaria at Zhob Garrison was studied by Khadim13 during the years 2000 and 2001 and found 665 patients positive for malaria out of 5650 cases. Yasinzai and Kakarsulemankhel14,15 investigated the incidence of malaria infection in urban and rural areas of Quetta district. Malaria Control Program (MCP) Balochistan in its yearly reports showed positivity rate 10.1%, P. vivax 6.6%, P. falci[parum 3.5%, 11.2%, 6.6%,4.6% and 12.7%, 8.2%, 4.4% in 2004, 2005, and 2006 respectively.16-18 Sheikh et al19 observed slide positivity 34.8% (91679/2,63,018) in Quetta during 1994-1998. While studying malaria in central areas of Balochistan (Mastung, Khuzdar districts), Yasinzai and Kakarsulemankhel20 observed 2092 (26.6%) confirmed cases of malaria out of 7852 in the year 2004-2006. In desert area of Balochistan, district Kharan, Yasinzai and Kakarsulemankhel21 reported slide positivity rate 43.4% (2432/5598) with a higher rate of 88.6% (2157/2432) prevalence of P. vivax than 11.3% (275/2432) of P. falciparum. However, the present study was carried out about the prevalence of malarial parasites in human populations residing in the districts of Loralai and Musakhel. District Kharan a desert in Balochistan.
Patients and Methods
A survey was conducted during July, 2004 to June, 2006 in 10, and 7 localities of Loralai and Musakhail districts respectively to record and screen the prevalence of species of malarial parasites from the blood of human patients suffering from malaria.
Loralai (Lat 30º,68º Long, Height 1430 M) and Musakhail (L31º, 69 ºL, H 1340 M) districts are situated at the eastern border of Balochistan province adjoining Dera Ghazi Khan and Tonsa Sharif area of the Punjab where there is high prevalence of human malaria. Malaria cases were detected byadapting two methods.22 Passive case (7158) detection (PCD) technique (where blood films were taken from the patients presenting themselves to a health center the other with symptoms of shivering and fever or a history suggestive of malaria) and active case (743) detection (ACD) (in which home visits were made to the persons with signs or symptoms of malaria and blood films both thin and thick were prepared). For ACD 10 high malarial prevalence localities in district Loralai and seven in Musakhail district were selected and house visits of suspected patients with malaria were made with the help of head/ Malik's of these localities. Blood slides were taken back to the laboratory where they were stained in Giemsa's stain.22 Identification of species of malarial parasites were made from the keys furnished by Sood.23 Species identification were based on these recommendations.
A total of 7899 blood smears (PCD:7158, ACD:743) were prepared from the age groups ranging from 1 year to 21 years and above residing in10 and seven different localities of[(t2)][(f3)][(f31)][(t21)][(t22)] Loralai and Musakhel respectively. However, variations were observed among different localities having different hygienic conditions.
The over all prevalence of Plasmodium slide positivity in both Loralai and Musakhail districts (Table 1-3) was observed to be 28.8% (2275/7899), where P. falciparum (Fig.1) was higher (71.8%:1633/2275) than of P. vivax. 28.2 % (642/2275) (Fig-2). Among slide positivity, in ages between 11-20 years 72.8% (629/864) were found to be of P. falciparum while in children between 1-10 years of age 72.6% (300/413), and in the age 21 years and above 70.5% (704/998). However, P. vivax was found to be less prevalent viz., 29.4% (294/998) in the age group of 21 years and above, 27.3% (113/413) in 1-10 years and 27.1% (235/864) in 11-20 years. We also noted seasonal variation in Loralai area with the highest (83.9%:287/342) infection of P. falciparum in September and lowest (65.3 %:34/52) in January. Whereas highest infection i.e. (34.6 %:(18/52) with P. vivax was noted in January and lowest i.e. 16% (55/342) in September (Table 1). In Musa Khail, the highest (76.9%: 30/39) infection of P. falciparum was in October and lowest (33.3 %:3/9) in February, whereas highest infection with P. vivax (66.6 %:6/9) in February and lowest (23%:9/39) in October (Table 3). In Loralai and MusaKhel area the primary vector species were A. culicifacies and A. stephensi.
Mixed infection of P. vivax and P. falciparum was not observed in the present study.
Data was statistically analyzed and no association was found between types of infection and age groups (P >0.05).
Malaria affects an estimated 300 million people and causes more than a million deaths per year worldwide. Falciparum malaria has high mortality as it causes complications like cerebral malaria, renal failure and algid malaria.5
In our study the high prevalence of P. falciparum (71.8%) than of P. vivax was observed 28.2%. Similarly, Akbar et al4 also noted 65% of P. falciparum in malaria patients in Children Hospital, Baqai Medical University, Karachi, Yasinzai and Kakarsulemankhel14,15 (65.8%) in Quetta rural and 55.5% in urban area. Slide positivity rate was 16.2% in Quetta rural and 15.4% in Quetta urban as compared to 28.8% (2275/7899) in both districts of Loralai and Musakhel.
No mixed infection was observed by Yasinzai and Kakarsulemankhel14,15 in rural and urban areas of Quetta district, in Mastung and Khuzdar districts20 respectively. However, mixed infection of plasmodia was seen in 2.3% in Quetta district,19 3.4% at Ayub Teaching Hospital Abbottabad,11 18.3% in Iranian part of south-east of Caspian Sea.24 We in our study also did not find any mixed infection. P. malariae and P. ovale were not seen by us, nor seen by Idris et al.11
In conclusion, the high prevalence rate 71.8 % (1633/2275) of P. falciparum poses a significant health hazard.
This study received financial support from the Higher Education Commission, Islamabad (Pakistan) through Balochistan University, under promotion of research, which is gratefully acknowledged.
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