Serologic Survey of Spotted Fever Group Rickettsiosis on Hainan Island of China

Abstract

A serosurvey for antibodies to Rickettsia japonica was conducted on Hainan Island of China. Serum specimens were collected from 1,030 outpatients at hospitals in different parts of the island regardless of their diagnosis. Only two among 538 serum specimens collected in Baoting and Tongshi counties, located in the southern part of the island, were demonstrated to contain antibodies reactive with R. japonica at a high dilution. The specimens also reacted with R. rickettsii at the same titer as with R. japonica. These two specimens reacted with other pathogenic spotted fever group (SFG) rickettsiae to a lesser extent. On the other hand, the specimens were shown to possess antibodies reactive with R. typhi at a significantly lower dilution or were not reactive at all. The findings suggested the occurrence of an SFG rickettsiosis on Hainan Island. More than half of the serum specimens collected from patients with suspected rickettsial infections in the southern area were found to contain IgM and IgG antibodies to R. typhi, indicating a high incidence of murine typhus.

Rickettsia japonica Infections in Humans, Xinyang, China, 2014–2017

“…hystrici s ticks in Wuhan, China, further corroborated this hypothesis ( 10 ). Also, serologic responses to R. japonica were detected in patients in Hainan Province in southern China ≈3 decades ago ( 11 ). However, laboratory-confirmed JSF cases have been identified in only a few patients in China ( 12 , 13 ).…”

Serological Survey of Spotted Fever Group Rickettsia in Wild Rats in Thailand in the 1970s

“…Although the disease was found in the southwestern part of Japan, Uchida et al hypothesized that R. japonica may exist outside Japan, possibly in southern China or Southeast Asia (12). The existence of SFGR on Hainan Island in China has been reported, although it has not been confirmed to be R. japonica (2).…”