|Year : 1997 | Volume
| Issue : 3 | Page : 89-92
Distribution of malarial parasites : Effect of gender of construction workers
PP Venugopalan1, D Urmila Shenoy2, Asha Kamath3, A Rajeev1
1 Department of Community Medicine, K.M.C., Mangalore, India
2 Department of Pathology, K.M.C., Mangalore, India
3 Department of Community Medicine, K.M.C., Mangalore-575 001, Karnataka State, India
Department of Community Medicine, K.M.C., Mangalore
|How to cite this article:|
Venugopalan P P, Shenoy D U, Kamath A, Rajeev A. Distribution of malarial parasites : Effect of gender of construction workers. Indian J Med Sci 1997;51:89-92
|How to cite this URL:|
Venugopalan P P, Shenoy D U, Kamath A, Rajeev A. Distribution of malarial parasites : Effect of gender of construction workers. Indian J Med Sci [serial online] 1997 [cited 2015 Mar 30];51:89-92. Available from: http://www.indianjmedsci.org/text.asp?1997/51/3/89/11526
The male predominance in descriptive studies of malaria without population base seems to be rather common. It is often attributed to the frequent exposure to vectors, the males are subjected to, compared to the better-clad and indoor-dwelling females in India.  There appears a lack of information regarding equally exposed groups of male and female cohorts to malaria. In this article we present a cross-sectional study which describes the hidden as well as overt infection in groups of migrant urban construction workers living in substandard tin sheds during peak transmission season of malaria in the city of Mangalore, South India.
| ¤ Material and Methods|| |
A haemo-parasitological and clinical survey was undertaken among construction workers during the peak transmission season of malaria in Mangalore, which happens to be July to August. All major building sites holding 50 or more workers were selected for the survey. Complete coverage was ensured to the maximum extent possible by fixing the date of survey to the convenience of the site supervisor and the Corporation Health Office. Total coverage was 2196 including children of the workers. A proforma for the sitesurvey and line-listing of all the workers with details such as duration of stay and clinical information was used. The survey teams consisted of staff and interns of the department of Community medicine, Kasturba Medical College and the experienced malaria surveillance teams from the health services augmented by Mangalore City Corporation officials. The time-tested thick and thin smear techniques were followed and the staining was done by the district malaria laboratory using JSB stain. Slides were examined for malarial parasites by the Pathology department of species identification was carried out in positive cases.
The statistical analysis was carried out for age sex, clinical symptoms and the species concerned using X 2 test and logistic regression.
| ¤ Results|| |
Out of the total population of 2196 studied 1631 were males and 565 females. At the time of visit 750 (34.2%) persons complained of fever with or without chills and/ or headache and/or malaise. All symptomatic persons were put on presumptive treatment to cut transmission to NMEP schedule. The results of the blood examination for malarial parasites (M.P.) were as foils. The slide positivity rate was 6.28%. When taken separately, males had 5.8% and females had 7.6%. This showed an almost similar rate of infection in both the sexes (p>0.05, NS). The higher number of infection noticed among the male population apparently reflect the proportionate predominance of males in the study group. Among the species of plasmodia, Pm falciparum was more prevalent in females (19% vs. 13%) than males. The reasons for this finding could not be established and might require more investigations. Age-wise 15 to 45 yr. age-group was predominantly affected. Second Commonest group was 5-14 years of age.
Importance of clinical symptoms for diagnosis was assessed in both males and females. The sensitivity of symptoms as a pointer to diagnosis was 58.95% and 55.8% respectively. Logistic regression showed that females were 1.48 more (p<001) likely to report any symptom compared to males. The OR (Odds Ratio) for P. vivax for producing symptoms was 2.5 (p<.001) as compared to MP negative cases whereas with P. falciparum plus mixed cases it was 4.25 (p=.004). However, the smear positivity was only related to symptoms and not to the sex of the subject. Symptomatic individuals were 2.687 times likely to have malaria than asymptomatics.
| ¤ Discussion|| |
The overall prevalence of malarial parasites with or without symptoms can be as high as about 50%> in adults of high endemic areas as Garki Project demonstrated.  Young age groups were particularly susceptible. Comparison of sexes showed high average parasite rates/parasite densities in males after the age of 5 years. This had been speculated elsewhere as due to possible influence of testosterone on parasitic diseases. 1048 Ghanaian children surveyed showed weighed overall means of parasitemia of lower magnitude in females,  but, did not show any major difference in overall parasite rates between males and females. The present study also failed to demonstrate any statistical difference in parasite prevalence among females and males. Social, residential or clothing factors leading to difference in exposure to malarial vector were much more uniform in this study group than any other population studied so far. Only difference was that she predominant species in this part of the world was P. vivax. Smear positivity was found related to the presence of symptoms Clinical criteria viz. fever, vomiting, splenomegaly etc. have been found useful in improving the diagnosis of malaria even in endemic areas in spite of high asymptomatic case rate.  Symptoms might be more suggestible of malaria if the subject were a male or if the parasite were P. falciparum. The latter hypothesis needs further research proof.
| ¤ Conclusions|| |
The study brings out the rising trends in malaria prevalence in migrant labourers in Mangalore. This is a relatively recent development, considering spun in building activities after 1990. The high asymptomatic reservoir of infection in such unprotected groups of population helps spread the infection to the surrounding areas investigation into the problem revealed the equal prevalence rates of plasmodia in both the sexes contrary to the belief that males are commoner preys to the infection. The study also supports the strategy of mass radical treatment in such agglomerations in view of high point prevalence rates during peak season and presumptive treatment for malaria for all symptomatic individuals.
| ¤ Summary|| |
The city of Mangalore in South India was having increasing number of malaria cases from 1990. Concerned over the import of cases through migrant construction workers, a screening was done among them using clinical and parasitological methods. This demonstrated 6.28% slide positivity rate with statistically insignificant difference in prevalence of infection between males and females. There were many asymptomatic individuals reporting positive only on peripheral smear examination. Yet, clinical symptoms like fever were found to have good predictive value on logistic regression. I was more so with the P. falciparum which is a relatively new entrant to Mangalore.
| ¤ Acknowledgements|| |
The authors thank the Malaria Control Action Committee of Mangalore for supporting the programme by providing vehicles and educational materials. Corporation officials were very much helpful in arranging the sites on a dayto-day basis. The health services personnel provided the muchneeded expertise for collecting perpheral-smears and the district malaria laboratory for staining the smears. The interns of Kasturba Medical College provided the treatment support to the programme. Staff members of department of Pathology as well as community Medicine were generous enough to oversee the whole operations. We thank them.
| ¤ References|| |
|1.||Parks Textbook of Preventive and Social Medicine 13th edition. M/s Bhanarsidas Bhanot, Jabalpur. 1991:Page 172. |
|2.||M61ineaux L, Gramiccia G. The Garki Project. WHO Geneva 1980; 122-125. |
|3.||Barbara L, Herwig K, Gerhard W, Walther HW. Parasite density of P. falciparum in Ghanaian school children : Evidence for influence of sex hormones. Transactions of the Royal Society of Tropical Medicine and Hygiene 1994:88:73-74. |
|4.||Genton B, Smith T, Baea K, Narara A. et al. Malaria : Howuseful are clinical criteria for improving the diagnosis in a highly endemic area. Transactions of the Royal Society of Tropical Medicine and Hygiene 1994:88:537-541. |
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