Outbreak of Scrub Typhus in Southern India during the Cooler Months

Abstract

Orientia tsutsugamushi, the agent of scrub typhus, is a strict intracellular bacterium which is found in many parts of Asia including India. During the past few years, the number of patients with rickettsial infection and scrub typhus has increased, especially during the cooler months. We report in this study a recent outbreak of scrub typhus recorded during the cooler months (October 2001 to February 2002) in patients admitted to our hospital with acute febrile illness associated with diverse signs and symptoms. Overall, 28 patients were clinically and serologically confirmed to have scrub typhus. Fever for more than one week was the only common manifestation. Myalgias was the next most common feature (52%), and rash was observed in only 22% of the cases. Seventeen patients treated with doxycycline recovered in 1 to 3 days, as well as two patients who received chloramphenicol. In five patients who received ciprofloxacin, fever subsided only after five days. Finally three patients (10.7%) died, including one patient treated with doxycycline. These data indicate that scrub typhus is a reemerging infectious disease in India with a possibility of drug resistance. This reemergence emphasizes the need for further prospective studies to design effective control measures.

Intrinsic fluoroquinolone resistance in Orientia tsutsugamushi

“…In an outbreak in Southern India, among 28 patients serologically confirmed to have scrub typhus, 17 patients treated with doxycycline and 2 patients treated with chloramphenicol recovered in 1-3 days [9].…”

“…Although doxycycline and chloramphenicol remain the gold standard therapy for scrub typhus, ciprofloxacin has been shown to be effective in a mouse model [4] and in some anecdotal clinical cases [5][6][7]. However, recent reports of clinical failure and deaths as well as abortions in pregnant women with fluoroquinolone therapy suggest drug resistance in these cases [8][9][10]. Fluoroquinolone activity is due to inhibition of bacterial DNA gyrase (topoisomerase II) and topoisomerase IV.…”

Does the presence of an eschar correlate with severity of scrub typhus infection?

“…[5][6][7] Its incidence in certain parts of India reaches endemic proportions and accounts for up to 50% of undifferentiated febrile illness in those areas during cooler months of the year. [3,7] The clinical finding of a pathognomonic eschar in a patient with febrile illness is the most important clue to the diagnosis of ST. The eschar usually forms 7 days after inoculation, and is usually not noticed by the patients however, as the chigger bite is painless.…”

“…[3,4] It is a clinically important disease because it is associated with many serious complications and has a mortality rate of 14-20%. [5][6][7] Its incidence in certain parts of India reaches endemic proportions and accounts for up to 50% of undifferentiated febrile illness in those areas during cooler months of the year.…”

"Candidatus Rickettsia kellyi," India

“…Nevertheless, these diseases are not well described in the literature and, to date, only serologic evidence of rickettsial infections has been reported, including murine typhus, scrub typhus, and unidentified spotted fever group (SFG) rickettsiosis ( 1 , 3 , 4 ). Moreover, the results of serologic testing are presumptive and should be interpreted with caution.…”