Surveillance of Schistosoma japonicum Infection in Domestic Ruminants in the Dongting Lake Region, Hunan Province, China

Background: Schistosomiasis japonica is prevalent in Asian countries and it remains a major public health problem in China. The major endemic foci are the marsh and lake regions of southern China, particularly the Dongting Lake region bordering Hunan and Hubei provinces, and the Poyang Lake region in Jiangxi province. Domestic ruminants, especially bovines, have long been considered to play a major role in the transmission of Schistosoma japonicum to humans. Methods and Findings: A miracidial hatching technique was used to investigate the prevalence of S. japonicum infections in domestic ruminants and field feces collected from two towns located to the south and east of Dongting Lake, Hunan province, between 2005 and 2010. The overall prevalence of infection was not significantly reduced from 4.93 % in 2005 to 3.64 % in 2008, after which it was maintained at this level. Bovines comprised 23.5–58.2 % of the total infected ruminants, while goats comprised 41.8–76.5%. Infection rates in cattle and goats were significantly higher than those found in buffalo in most study years. The prevalence in buffalo younger than three years was significantly higher than that in those aged over three years. All the positive field samples of feces were derived from bovines in Nandashan. In Matang Town, 61.22 % of the positive field feces were from bovines, while the rest were from goats. The positive rates for field feces were approximately the same in April and November/October. Conclusions: The present study found that bovines and goats are major sources of S. japonicum infection in the Dongtin

Overall prevalence and the number of infected domesticated ruminants.

<p>*The infected number of bovines was the sum of numbers of cattle and buffaloes, which were calculated with their total number (data not shown) and prevalence (in <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0031876#pone-0031876-t002" target="_blank">table 2</a> and <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0031876#pone-0031876-t003" target="_blank">3</a>) from each town. The numbers in brackets were from Matang Town.</p

Positive rates in field feces.

<p>Positive rates in field feces.</p

Prevalence of <i>S. japonicum</i> infection in cattle and buffalo from Nandashan Town.

<p>*<i>P</i><0.05;</p><p>**<i>P</i><0.01 comparison of prevalence between cattle and buffalo.</p

Prevalence (%) of <i>S. japonicum</i> infection in bovines of different ages.

<p>*P<0.05;</p><p>**P<0.01 comparison of buffaloes younger and older than three years. C.N.,Cattle from Nandashan Town; B.N., Buffaloes from Nandashan Town; B.M., Buffaloes From Matang Town.</p

Prevalence of <i>S. japonicum</i> infection in buffalo and goats from Matang Town.

<p>*<i>P</i><0.05;</p><p>**<i>P</i><0.01 comparison of prevalence between buffalo and goats.</p>#<p><i>P</i><0.01 comparison of prevalence with that in 2005.</p