Rickettsial Infections and Q Fever Amongst Febrile Patients in Bhutan

Abstract

There is limited evidence of rickettsial diseases in Bhutan. We explored the contribution of rickettsioses as a cause of undifferentiated febrile illness in patients presenting to 14 Bhutanese hospitals from October 2014 to June 2015. Obvious causes of fever were excluded clinically. Clinico-demographic information and acute blood samples were collected. Samples were tested by immunofluorescence assay (IFA) and qPCR against scrub typhus group (STG), spotted fever group (SFG) and typhus group (TG) rickettsiae, and Q fever (QF). Of the 1044 patients, 539 (51.6%) were female and the mean age was 31.5 years. At least 159 (15.2%) of the patients had evidence of a concurrent rickettsial infection. Of these, 70 (6.7%), 46 (4.4%), 4 (0.4%), and 29 (2.8%) were diagnosed as acute infections with STG, SFG, TG, and QF respectively. Ten (1.0%) patients were seropositive for both SFG and TG. Seven of the 70 STG patients were positive by qPCR. Eschar (p < 0.001), myalgia (p = 0.003), and lymphadenopathy (p = 0.049) were significantly associated with STG, but no specific symptoms were associated with the other infections. Disease incidences were not different between age groups, genders, occupations, and districts, except for students with significantly lower odds of infection with STG (OR = 0.43; 95% CI = 0.20, 0.93; p = 0.031). Rickettsioses were responsible for at least 15% of undifferentiated febrile illnesses in Bhutan, scrub typhus being the commonest. Health authorities should ensure that health services are equipped to manage these infections.

Rickettsial infections of the central nervous system

“…tsutsugamushi and O . chuto [123], that cause scrub typhus, which is still regarded by some experts as a rickettsiosis, and are closely related to Rickettsia species [124,125]. Scrub typhus is a common cause of febrile illness in Asia.…”

Confirmation of local transmission of Orientia tsutsugamushi during scrub typhus outbreaks in Nepal

“…We cannot discount the possibility of other rodent species associated with scrub typhus in Nepal. Although we did not cover other rickettsial diseases, cases of spotted fever group, typhus group and Q Fever rickettsia in scrub typhus endemic areas of the neighbouring countries like India [18] and Bhutan [6] warrant further investigation of these etiologies in Nepal. Moreover, recent indication of Q fever in some acute undifferentiated febrile cases in Nepal also underscores it [21].…”

“…However, there have been recent reports of scrub typhus from Africa, France, the Middle East, and South America suggesting the disease is no longer restricted to this triangle [2]. Scrub typhus is frequently reported from many Asian countries and is endemic in Nepal's neighboring countries including India (Sub-Himalayan belt) and Bhutan, where it is considered an emerging infectious diseases [3][4][5][6]. In Bhutan, one in six undifferentiated febrile patients had rickettsial infections, with scrub typhus being the most common [6].…”

“…Scrub typhus is frequently reported from many Asian countries and is endemic in Nepal's neighboring countries including India (Sub-Himalayan belt) and Bhutan, where it is considered an emerging infectious diseases [3][4][5][6]. In Bhutan, one in six undifferentiated febrile patients had rickettsial infections, with scrub typhus being the most common [6]. However, the disease situation in Nepal has remained silent until now, likely due to the high burden of other febrile illnesses with indistinguishable clinical signs and limited proper diagnostic availability.…”

“…established nature of scrub typhus outbreaks in Nepal through evidences of the causative agent O. tsutsugamushi in human (patients), animals (rodents) and vector/ reservoir hosts (chigger mites) during the recent fatal outbreaks. Despite the frequent reports of outbreaks from neighbouring countries, particularly India and others[3][4][5][6][17][18][19][20], scrub typhus remained silent in Nepal for decades after its first indication in 1981[7].…”