J. H. Park

Tick-Borne Rickettsial Pathogens in Ticks and Small Mammals in Korea

ABSTRACT In order to investigate the prevalence of tick-borne infectious agents among ticks, ticks comprising five species from two genera (Hemaphysalis spp. and Ixodes spp.) were screened using molecular techniques. Ticks (3,135) were collected from small wild-caught mammals or by dragging/flagging in the Republic of Korea (ROK) and were pooled into a total of 1,638 samples (1 to 27 ticks per pool). From the 1,638 tick samples, species-specific fragments of Anaplasma phagocytophilum (1 sample), Anaplasma platys (52 samples), Ehrlichia chaffeensis (29 samples), Ehrlichia ewingii (2 samples), Ehrlichia canis (18 samples), and Rickettsia rickettsii (28 samples) were amplified by PCR assay. Twenty-one pooled and individual tick samples had mixed infections of two (15 samples) or three (6 samples) pathogens. In addition, 424 spleen samples from small captured mammals (389 rodents, 33 insectivores, and 2 weasels) were screened for selected zoonotic pathogens. Species-specific DNA fragments of A. phagocytophilum (110 samples), A. platys (68 samples), E. chaffeensis (8 samples), E. ewingii (26 samples), E. canis (51 samples), and Rickettsia sp. (22 samples) were amplified by PCR assay. One hundred thirty small mammals had single infections, while 4, 14, and 21 striped field mice (Apodemus agrarius) had mixed infections of four, three, and two pathogens, respectively. Phylogenetic analysis based on nucleotide sequence comparison also revealed that Korean strains of E. chaffeensis clustered closely with those from China and the United States, while the Rickettsia (rOmpA) sequences clustered within a clade together with a Chinese strain. These results suggest that these agents should be considered in differential diagnosis while examining cases of acute febrile illnesses in humans as well as animals in the ROK.

Prevalence of brucellosis and its association with reproductive problems in cows in Bangladesh

Brucellosis is one of the worlds major zoonoses, alongside bovine tuberculosis and rabies. Brucella species infection is endemic in human beings and livestock in Mediterranean countries, and it is also present in Asia, sub-Saharan Africa and Latin America. The importance of brucellosis is not known precisely, but it can have a considerable impact on both human and animal health, as well as having socioeconomic effects, especially in areas where rural income relies largely on livestock breeding and dairy products. Brucellosis in human beings is caused by exposure to livestock and livestock products. Infection can result from direct contact with infected animals and can also be transmitted to consumers through raw milk and milk products. In human beings, the symptoms of disease are weakness, joint and muscle pain, headache, undulant fever, hepatomegaly, splenomegaly and night sweats. Recently, it has been reported that brucellosis can affect the central and peripheral nervous system. In animals, brucellosis mainly affects reproduction and fertility, reduces the survival of newborns and reduces milk yield. The disease does not cause significant mortality in adult animals. In Bangladesh, approximately 80 percent of people live in villages, and rural income is largely dependent on livestock; the people are in close contact with livestock on a daily basis. There are about 33.55 million goats