The majority of cockroaches from the Samutprakarn province of Thailand are carriers of parasitic organisms

Abstract

We undertook a study of the mechanical transmission of parasitic organisms in cockroaches in the Samutprakarn province of Thailand. In this study, 920 cockroaches were obtained from 18 open-air shopping markets in 5 districts and 1 subdistrict of this province. All cockroaches were captured during their feeding time in their natural habitat. Direct wet smear and modified acid-fast bacilli staining were used to identify the parasites from the external surface or cuticle of the cockroaches. The results show that 498 (54.1 %) of the cockroaches harbored parasitic organisms. Of these, 56.1 % were protozoa and the remaining 43.9 % were helminthes (pathogenic helminthes- 1.4 %, non-pathogenic helminthes- 42.5 %). Of the pathogenic helminthes, the species included Strongyloides stercoralis (6 instances of the free-living adult male, 0.8 %), Ascaris lumbricoides (2 decorticated eggs, 0.3 %), Trichuris trichiura (2, 0.3 %), and Taenia spp. (1 egg, 0.1 %). The protozoa types that were identified included Cyclospora spp. (10 oocysts, 1.3 %), Endolimax nana (10 cysts, 1.3 %), B. hominis (9 instances of the vacuolated form, 1.2 %), Isospora belli (75 oocysts, 9.6 %), Entamoeba histolytica/E. dispar (36 cysts, 4.6 %), Cryptosporidium spp. (220 oocysts, 28.1 %), Chilomastix mesnilli (2 cysts, 0.3 %), Entamoeba coli (31 cysts, 4.0 %), Balantidium coli (45 trophozoites, 5.8 %), and Iodamoeba butschlii (1 cyst, 0.1 %). These results show that cockroaches isolated from these markets are carriers of several parasitic organisms that cause commonly found symptoms of illness such as diarrhea or bowel disorder.