Infections Of Piroplasms In Different Hosts In Xinyang, Henan Province

Piroplasmosis is a tick-borne disease which caused by infection with apicomplexan protozoa, such as the Babesia and the Theileria species. These protozoan parasites are transmitted by vector ticks and can infect many different species of domestic and wild animals. Theileriosis and babesiosis are distributed widely in China causing great economic losses. Some Babesia species, such as B. microti and B. divergens, are the major pathogenetic species of piroplasms causing human infections, however some Theileria species can also cause severe acute disease in humans as human theileriosis. Symptoms of human infections with piroplasms may include malaise, chills, anemia, fatigue, and fever, nausea, emesis, night sweats, weight loss, and hematuria. Some cases may lead to organ failure and death.Ticks (Acari:Ixodida) are parasitic acari that suck blood from their vertebrate hosts. They can transmit a number of pathogenic organisms to humans and domestic animals and cause a variety of important natural focal diseases and zoonoses. Ticks are important pests and vectors of several pathogens in tropical and subtropical regions. To date, more than900species of ticks have been recorded globally. In China, about eleven genera of ticks have been recorded which covered approximately120species, including10species of Argasidae and over100species of Ixodidae. Tick species are specifically distributed in different zones in China. The distribution of ticks and tick-borne pathogens varied in different provinces in China with uneven distribution in space and time. Tick-borne diseases were mostly reported in northern and northeastern parts of China, such as Xinjiang, Inner Mongolia, Heilongjiang, Jilin, Liaoning and Yunnan provinces. It has been reported that one tick species can transmit a variety of pathogens, and several kinds of tick borne diseases often co-exist in the same tick species which make the transmission of tick borne diseases a more complex process.Recently, Tick borne diseases have been recently reported in China.98%of the total cases (>1000) were reported in Xinyang city, Henan provinces. Although there has been no report of human babesiosis in Xinyang yet, we suspected that some cases have been misdiagnosed as other infections, such as Plasmodium infection, since Plasmodium spp. was once heavily endemic in these areas. Until now, the characteristic of transmission of the Babesia and Theileria species in different hosts is still unclear. Thus, we investigated the infections of Babesia spp. and Theileria spp. in different hosts including vector ticks, domestic and wild animals and human beings in Xinyang city, in order to analyze the distribution patterns of piroplasms infections and assess their potential threat to humans.First, an investigation was conducted from April to December2012in10different villages located in8counties and2districts in Xinyang city. The sampling sites were determined by a method of random grid sampling, which was performed using ArcGIS. Ticks were collected once in each sampling site from the skin of domestic animals including sheep, cattle and dogs. The tick species were identified by using morphologic criteria method and PCR. Nested PCR was used for detection of Babesia spp. and Theileria spp. in this study. A total of308ticks were collected in10villages. Only two tick species were sampled, and both of them were Ixodidae. The most abundant species was H. longicornis (96.75%). The other one was R. microplus (3.25%). Babesia spp. was detected from ticks in Luoshan, Huangchuan, Shangcheng and Xi counties, and their positive rates were1.69%,5.71%,4.65%and1.69%, respectively. Theileria spp. was detected from ticks in Shihe district and Guangshan county, and the positive rates were21.88%and15.79, respectively. No positive tick had been found in the other four villages. In this study, two Theileria (T. buffeli and T. luwenshuni) and three Babesia (B. gibsoni, B. carnis vogeli and B. microti) species were identified.Then, we investigated the infections of Babesia and Theileria species in both domestic and wild animals in5counties, including Luoshan, Shihe, Pingqiao, Shangcheng and Xi counties from April to December2013. The sampling sites were determined by a method of random grid sampling based on the results of the previous study in2012. A total of531blood samples were collected from hedgehogs, sheep, dogs, cattle and chicken. Babesia spp. was detected in Shangcheng, Shihe and Xi counties, and the positive rate was0.98%,0.99%and1.89%, respectively. Theileria spp. was detected in Shihe, Pingqiao, Shangcheng and Luoshan counties, and the positive rate was43.40%,64.71%and14.05%, respectively. Two Babesia (B. gibsoni and B. microti) and one Theileria (T. luwenshuni) species were identified in this study. The results indicated that T. luwenshuni was the predominant Theileria species in these regions. It’s very close to Theileria sp., in term of genetic distances, isolated from a febrile hospitalized patient from Suizhou city of Hubei province.Thus, an investigation of the infections of Babesia and Theileria species in humans among the high-risk groups was also carried out in Pingqiao, Shangcheng and Xi counties from August to October2013. A total of310blood samples were collected from febrile patients or those with tick bites history. After screening those blood samples for piroplasms infections, two patients were tested infection with Babesia spp.. One patient from Xin county was found to be infected with B. microti. which was indentified by sequencing of18S rRNA gene.Then, in order to develop a fast screening techonogy for piroplasms infections, a study of co-infections of Babesia spp. and Theileria spp. was carried out by using reverse line blot hybridization assay (RLB) in those samples from vector ticks, animal hosts and humans. There was no co-infections of piroplasms was found in any samples. Finally, we analyzed the factors affecting infections of piroplasms among different hosts in Xinyang city by factors analysis and logistic regression method. The factors analysis revealed that normalized difference vegetation index (NDVI) was the common factor affecting infections of piroplasms among differnet hosts in Xinyang city.In conclusion, Babesia spp. and Theileria spp. infections were detected in different hosts in Xinyang in this study. The infection of B. microti was found in vector ticks, animal hosts and humans. T. luwenshuni was detected in vector ticks and animal hosts. Further studies are warranted to estimate the risks to local residence and animal husbandry by these vector ticks and pathogens in Xinyang region.