Rickettsial diseases: the typhus group of fevers—a review

Abstract

Epidemic louse borne typhus has historically caused massive mortality in the wake of war, famine, and great migrations.1 In the four years from 1918 in Eastern Europe and Russia there were up to 30 million cases, and three million deaths. In the recent past in Burundi typhus has infected prison inmates before spreading to the wider community.2 It remains a risk among refugee populations in all parts of the world, despite its omission from a recent review of health care in refugee camps.3

Rickettsial Infections in Southeast Asia: Implications for Local Populace and Febrile Returned Travelers

“…In addition, clearing of land for urban development and construction enable rodent populations to increase and expose humans to the zoonotic life cycle, thus leading to increasing seroprevalence observed in some of the rapidly developing countries, such as Malaysia. 19 More aggressive infections have also been reported in refugee camps, 2 and this finding may be significant for refugee populations along the Thailand-Myanmar border. It is important to note that imported murine typhus can be acquired after travel to exclusively urban areas.…”

“…O. tsutsugamushi is acquired from the bite of the larval stage of infected trombiculid mites (chiggers) living on the waist-high grass growing in previously cleared jungle around villages and plantations. 2,61 Chiggers have also been found on many rodent vectors. 29 Cases were acquired during land clearing, logging, road building, and military operations.…”

“…Eschar is variably seen in 20-90% of cases, typically on torso, axilla, or groin, and may be diagnostic (Figure 3). 2,28,52,64,65 Conjunctival suffusion can also occur. 41 Of all rickettsial diseases, scrub typhus is more likely to present with a severe clinical picture because of a more prominent inflammatory response, 42 which causes multiorgan dysfunction, meningoencephalitis, coma, and persistent neurologic deficits.…”

“…41 An eschar at the site of an ectoparasite bite, with local or generalized lymphadenopathy may also occur ( Figure 2). 2 The eschar may be the only clinical sign that differentiates scrub typhus and tick-borne SFG Rickettsia from other infectious diseases, including murine typhus. 28,41 Travelers with imported rickettsial diseases often become sick before or within a few days of returning from a disease-endemic region.…”

“…1 Overall, rickettsial infections rate as the second most frequently reported infections for non-malarial febrile illnesses among residents of Southeast Asia, just after dengue. 1 Rickettsioses also remain a substantial risk among refugee populations, 2 particularly those living along Thailand-Myanmar border, where they may contribute up to 33% of febrile illness presentations. 3 They are also associated with stillbirth in pregnancy or low birth weight in infants.…”