Incidence of parasitic infections of in- and outpatients at Maharaj Nakorn Chiang Mai hospital, Chiang Mai University, Thailand 2012-2016

Abstract

Objective The objective of this study was to determine the incidence of parasitic infections in in- and out-patients at Maharaj Nakorn Chiang Mai Hospital, Chiang Mai University, Thailand during the period 2012 through 2016.

Methods Stool, blood, and sputum samples of patients were examined for parasite infections at the laboratory of the Department of Parasitology, Faculty of Medicine, Chiang Mai University. Stool samples were examined for intestinal parasites using the formalin-ether concentration technique, modified acidfast staining, and simple smears. Stool and sputum samples were cultured for Strongyloides stercoralis using an agar plate technique. Blood samples were examined for malarial parasites using Giemsa staining of thick blood films.

Results During the five year study period, a total of 18,967 stool specimens were examined of which 1,268 (6.69%) were positive for at least one intestinal parasite. Helminthic infections were found in 6.02% of cases and 0.67% had protozoan infections. The most frequent helminth and protozoa among infected patients were S. stercoralis (58.60%) and Giardia lamblia (4.18%). The prevalence of malaria infection was 2.94%, with a higher positive rate for Plasmodium vivax (1.99%) than P. falciparum (0.95%). The annual incidence of intestinal parasites during the period 2012 through 2016 decreased significantly from 7.99% to 5.78%. Malaria infections between 2013 and 2016 also decreased from 3.23% to 1.76%, but the change was not statistically significant.

Conclusion There has been a decrease in the incidence of parasitic infections in patients presenting at the hospital over the study period. This may reflect improvement of the hygiene of people in northern Thailand in general. However, this information may not be representative of the parasitic infection situation of particular groups, e.g., hill tribe communities and other groups living in isolated rural areas.