The Re-Emergence and Emergence of Vector-Borne Rickettsioses in Taiwan

Abstract

Rickettsial diseases, particularly vector-borne rickettsioses (VBR), have a long history in Taiwan, with studies on scrub typhus and murine typhus dating back over a century. The climatic and geographic diversity of Taiwan’s main island and its offshore islands provide many ecological niches for the diversification and maintenance of rickettsiae alike. In recent decades, scrub typhus has re-emerged as the most prevalent type of rickettsiosis in Taiwan, particularly in eastern Taiwan and its offshore islands. While murine typhus has also re-emerged on Taiwan’s western coast, it remains neglected. Perhaps more alarming than the re-emergence of these rickettsioses is the emergence of newly described VBR. The first case of human infection with Rickettsia felis was confirmed in 2005, and undetermined spotted fever group rickettsioses have recently been detected. Taiwan is at a unique advantage in terms of detecting and characterizing VBR, as it has universal health coverage and a national communicable disease surveillance system; however, these systems have not been fully utilized for this purpose. Here, we review the existing knowledge on the eco-epidemiology of VBR in Taiwan and recommend future courses of action.

The estimated burden of scrub typhus in Thailand from national surveillance data (2003-2018)

“…Within each province, the population is served by a central provincial hospital, district hospitals and primary care or health promoting units located in every sub-district. There has been an increase in notified cases reported from other countries with established passive notification systems such as South Korea, China and Bhutan, while results from Japan and more recently Taiwan suggest the disease incidence has stabilised [15,[32][33][34][35][36][37].…”

Epidemiology and Diversity of Rickettsiales Bacteria in Humans and Animals in Jiangsu and Jiangxi provinces, China

“…Although murine typhus and epidemic typhus are considered to be controlled, at least 929 cases have been registered annually since 1999 (range 929 to 6149 cases) (unpublished data obtained from Infectious Disease Report Information Management system of China Center for Diseases Control and Prevention (CDC)). Scrub typhus initially emerged in northern China and then re-emerged in southern China 13,16,28 . In addition, although HGA and HME cases are commonly reported in Chinese hospitals, it is not clear how many cases have occurred each year in China as a whole.…”

“…Although scrub typhus occurs only in Asia, it is estimated that more than one million cases of the disease are transmitted annually with more than one billion people at risk 13–16,42 . Scrub typhus has a long history in China, leading to high morbidity and mortality in humans 27 , particularly in southern China 13,14,28 . Although chiggers (family Trombiculidae ) are thought to be the true reservoir of O .…”

A Brief History of the Major Rickettsioses in the Asia–Australia–Pacific Region: A Capstone Review for the Special Issue of TMID

“…Legendre and Macaluso [ 92 ] reviewed various procedures, including IFA, qPCR, and gene sequencing, that have contributed to insights on the biology of Rickettsia felis . Similarly, in their broad review of rickettsioses in Taiwan, Minahan et al [ 93 ] indicate how a number of tools, IFA, PCR, RFLP analysis, qPCR, and gene sequencing, have all been used to study a number of different rickettsial disease agents occurring in the island nation. Hardstone Yoshimiru and Billeter [ 94 ] perform a similar review of many tools used in the study of North American rickettsioses.…”

“…The case for treatment failures in scrub typhus has gained much attention in recent years [ 101 , 102 ], and summarized descriptions of the evidence have been presented elsewhere in the special issue of TMID [ 4 , 11 , 93 ]. Thus, in cases of doxycycline failure, azithromycin, 500 mg/day for 3 days, may be indicated [ 103 ].…”