Scrub typhus associated acute kidney injury

Abstract

Background & objectives: Acute kidney injury associated with scrub typhus is an emerging health problem in the tropics including India. This study intended to find out the incidence, clinical outcome, cytokine response and genotypes of Orientia tsutsugamushi associated with AKI patients in Odisha, a state in eastern India. Methods: Acute febrile illness or history of acute fever with various degrees of kidney involvement admitted to SCB Medical College Hospital, Cuttack were included in the study. A detailed demographic characteristics and clinical features were recorded with pre-tested questionnaire at the time of admission. Scrub Typhus was detected by ‘IgM ELISA’ test (OD > 0.5) and PCR. Routine urine, haematological and biochemical tests were performed. Genotyping of the Orientia tsutsugamushi was done using 56-kDa gene for Orientia species and phylogenetic tree by neighbor-joining method. The plasma level of the IFN-γ (pro-inflammatory cytokine) and IL10 (anti-inflammatory) were measured by commercially available ELISA kit. The statistical analysis was performed using Graph Pad Prism software (version 4). Results: Out of 140 acute febrile illness or history of acute febrile illness patients with AKI admitted to hospital, 32.14% were confirmed to be scrub typhus positive; eschar was seen in 17.8% of them. Of the total scrub typhus positive cases, 24.4% were having multi organ dysfunction. Majority of the AKI patients (60%) were in the “failure” category under RIFLE criteria. The mortality rate was 20.0%. Risk of dialysis requirement and mortality increases with RIFLE classification. “Karp” was the predominant circulating genotype. IFN-γ and IL10 level was high among the scrub typhus associated AKI patients. Interpretation & conclusion: The study shows a high incidence of scrub typhus associated AKI and high case fatality rate. Hence, emphasis should be given on differential diagnosis. RIFLE classification is applicable with increment risk of dialysis requirement and death. An in-depth study is required to determine the role of O. tsutsugamuchi KARP strain and INF-γ/ IL-10 in disease severity so as to identify a prognostic marker.

Development and implementation of a strategy for early diagnosis and management of scrub typhus: an emerging public health threat

“…There are certain programmatic “losses” envisaged through this framework, thus not all suspects may be identified at the community level and all identified suspects may not undergo screening/diagnosis. To summarize, it was presumed from anecdotal experiences that the suspicion index for scrub typhus among all categories of health workers, including physicians, was low and that diagnostic tests for this disease was not available in primary care ( 11 , 36 ). Therefore, these two components were identified as “rate limiting steps” for scrub typhus control and guided the design of the STCP so that the potential losses from the care cascade can be preemptively plugged and program effectiveness optimized.…”

“…However, the presence of an eschar in Indian and other Asian populations is rare, which makes it an inappropriate method for the diagnosis of scrub typhus. Therefore, the diagnosis predominantly depends on laboratory tests ( 11 ). Serological assays such as the Weil–Felix test, indirect immunofluorescence assays, indirect immune peroxidase assays, and enzyme-linked immunosorbent assay (ELISA) and immune chromatographic tests (ICTs) are the prominent tests employed to diagnose rickettsial diseases.…”

“…Meanwhile, the serological analysis undertaken by RMRC of 30 AES archived samples collected from hospitalized children during the 2016 epidemic from another district, Malkangiri, indicated that 23.3% (7/30) of the cases were positive for scrub typhus. Recently, high incidence of scrub typhus associated with acute kidney injury was reported among patients having a history of acute fever with various degrees of kidney involvement admitted to a tertiary care hospital ( 11 ).…”

“…As solid evidence of a considerable burden of scrub typhus in Odisha emerged from reports of tertiary care hospitals and the community-based study of the RMRC ( 11 , 36 ), there was a necessity to initiate a public health program that can be instituted to control this problem in the state so that many severe health conditions and fatalities related to scrub typhus at the population level can be averted in the long term.…”

“…Occasionally, the case fatality can be as high as 30%−70% in untreated cases (9,10). Furthermore, the wide genetic variability observed in the pathogen in India, such as Gillam, Karp, Hualien1, and Keto, and across the globe, along with complicated hostpathogen interactions, hinders the development of vaccine and improved diagnostic and therapeutic methods (8,(11)(12)(13)(14).…”