Abstract. Scrub typhus is endemic in Thailand. Of the 495 patients with acute undifferentiated fever studied in Maharat Nakhon Ratchasima Hospital, Nakhon Ratchasima, Thailand, from June 1, 2011, to December 31, 2012, 146 patients (29.5%) had confirmed scrub typhus. The majority of cases were male, farmers, with the mean (±standard deviation) age of 54.1 ± 15.2 years. A total of 59 patients (40.4%) had eschar lesion. The commonest sites for an eschar in male patients were the perineum, inguinal, and buttock area; whereas in females, it was the head and neck area. Abnormal electrocardiogram was found in 39 of 79 patients (49.4%) with sinus tachycardia being the most frequent finding (17, 21.5%). A total of 73 patients (50%) had at least one complication. Myocarditis was the cause of complete heart block in a scrub typhus patient, and he fully recovered after receiving intravenous chloramphenicol treatment. The case fatality rate was 6.2% (nine deaths).The independent predictors for fatal outcome were age over 65 years (odds ratio [OR] = 14.49, 95% confidence interval [CI] = 1.26-166.44, P = 0.03), acute kidney injury (OR = 12.75, 95% CI = 1.77-92.07, P = 0.01), and hyperbilirubinemia (OR = 24.82, 95% CI = 2.12-286.61, P = 0.01). Early diagnosis and prompt appropriate treatment can improve the patient's outcome.
BackgroundOpportunistic infections represent a serious health problem for HIV-infected people. Among enteric infections, cryptosporidiosis, a severe and life-threatening diarrheal disease, is of particular importance in low economic settings where access to anti-retroviral therapy is limited. Understanding transmission routes is crucial in establishing preventive measures, and requires the use of informative genotyping methods. In this study, we performed a retrospective analysis of Cryptosporidium species in 166 stool samples collected from 155 HIV-infected patients during 1999–2004 at the Siriraj Hospital in Bangkok, Thailand.ResultsMicroscopic examination of stools identified 104 of the 155 patients as positive for Cryptosporidium. Other common pathogens identified were microsporidia, Isospora, Giardia, Strongyloides and Opisthorchis. All samples were tested by amplification of a fragment of the 18S rDNA locus, and sequencing showed the presence of Cryptosporidium hominis (n = 42), C. meleagridis (n = 20), C. canis (n = 12), C. felis (n = 7), C. suis (n = 6) and C. parvum (n = 5). Genotyping at the glycoprotein 60 (gp60) locus revealed substantial variability in isolates of C. hominis and C. meleagridis. Among C. hominis isolates, subtype IeA11G3T3 was the most prevalent, but allelic family Id was the more diverse with four subtypes described, two of which were identified for the first time. Among C. meleagridis isolates, seven subtypes, two of which were new, were found in the allelic family IIIb, along with new subtypes in allelic families IIIe and IIIg. In the four C. parvum isolates, subtype IIoA16G1, a rare subtype previously reported in a Swedish patient who had traveled to Thailand, was identified.ConclusionsThis study confirms the high susceptibility of HIV-infected individuals to infection with different Cryptosporidium species and subtypes, and further stresses the importance of surveillance for opportunistic intestinal protozoans.Electronic supplementary materialThe online version of this article (10.1186/s13071-019-3348-4) contains supplementary material, which is available to authorized users.
Scrub typhus, caused by Orientia tsutsugamushi, is a common cause of acute undifferentiated febrile illness in the Asia-Pacific region. However, its nonspecific clinical manifestation often prevents early diagnosis. We propose the use of PCR and serologic tests as diagnostic tools. Here, we developed a multiplex real-time PCR assay using hydrolysis (TaqMan) probes targeting O. tsutsugamushi 47-kDa, groEL, and human interferon beta (IFN- gene) genes to improve early diagnosis of scrub typhus. The amplification efficiency was higher than 94%, and the lower detection limit was 10 copies per reaction. We used a human gene as an internal DNA quality and quantity control. To determine the sensitivity of this PCR assay, we selected patients with confirmed scrub typhus who exhibited a clear 4-fold increase in the level of IgG and/or IgM. The PCR assay result was positive in 45 of 52 patients, indicating a sensitivity of 86.5% (95% confidence interval [CI]: 74.2 to 94.4). The PCR assessment was negative for all 136 non-scrub typhus patients, indicating a specificity of 100% (95% CI: 97.3 to 100). In addition, this test helped diagnose patients with inconclusive immunofluorescence assay (IFA) results and using single blood samples. In conclusion, the real-time PCR assay proposed here is sensitive and specific in diagnosing scrub typhus. Combining PCR and serologic tests will improve the diagnosis of scrub typhus among patients presenting with acute febrile illness.KEYWORDS Orientia tsutsugamushi, real-time PCR, scrub typhus S crub typhus is a mite-borne infectious disease caused by the obligate intracellular bacterium Orientia tsutsugamushi. A characteristic feature of the disease is patients presenting nonspecific symptoms, including fever, headache, myalgia, cough, and abdominal pain, which cannot be differentiated from symptoms of other systemic infections. The presence of eschar can help diagnose this illness; however, it is found only in some patients (1). Although the clinical course of scrub typhus is usually mild and self-limiting, delaying the treatment in severe cases can lead to complications such as renal failure, myocarditis, meningoencephalitis, and death (2). Since scrub typhus is one of the most common causes of acute undifferentiated febrile illness (AUFI) in areas of endemicity (3, 4), an early, definite diagnosis is essential for providing appropriate treatment and gathering accurate epidemiological data.Scrub typhus diagnosis mainly relies on serologic tests, particularly the indirect immunofluorescence assay (IFA), whereby the illness is identified by a 4-fold increase in antibody titers in paired sera (5, 6) and/or a positive IgM titer in a single serum sample (7,8). However, these serologic tests require paired serum samples and good technician expertise, and even then they often return false negatives during the early phase of disease. In addition, reinfection by different O. tsutsugamushi strains is not uncommon in areas of endemicity and reinfected patients may sometimes
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