Scrub Typhus and Other Rickettsial Infections

Scrub typhus and other rickettsial infections contribute to 25 - 50% of acute undifferentiated febrile illnesses in endemic regions. Delayed recognition and therapy increase the morbidity and mortality. The constellation of fever with eschar or rash and multisystem involvement should facilitate the diagnosis and initiation of appropriate therapy. The pathological hallmark of rickettsial infections is endothelial infection and inflammation causing vasculitis. Endothelial inflammation results in microvascular dysfunction and increased vascular permeability. Immune and endothelial activation may worsen microvascular dysfunction, predisposing to multi-organ failure. Serology is the mainstay of diagnosis, although false negatives occur early in the disease. Point-of-care rapid diagnostic tests and molecular techniques, such as quantitative polymerase chain reaction (qPCR), can hasten diagnostic processes. Intravenous doxycycline with a loading dose is the most widely used antibiotic in critically ill patients, with azithromycin as a suitable alternative. Early appropriate treatment and organ support can decrease the duration of illness and be life-saving. How to cite this article: Gunasekaran K, Bal D, Varghese GM, et al. Scrub Typhus and Other Rickettsial Infections. Indian J Crit Care Med 2021;25(Suppl 2):S138-S143.

Exploring rotavirus proteome to identify potential B- and T-cell epitope using computational immunoinformatics

Rotavirus is the most common cause of acute gastroenteritis in infants and children worldwide. The functional correlation of B- and T-cells to long-lasting immunity against rotavirus infection in the literature is limited. In this work, a series of computational immuno-informatics approaches were applied and identified 28 linear B-cells, 26 conformational B-cell, 44 T_C cell and 40 T_H cell binding epitopes for structural and non-structural proteins of rotavirus. Further selection of putative B and T cell epitopes in the multi-epitope vaccine construct was carried out based on immunogenicity, conservancy, allergenicity and the helical content of predicted epitopes. An in-silico vaccine constructs was developed using an N-terminal adjuvant (RGD motif) followed by T_C and T_H cell epitopes and B-cell epitope with an appropriate linker. Multi-threading models of multi-epitope vaccine construct with B- and T-cell epitopes were generated and molecular dynamics simulation was performed to determine the stability of designed vaccine. Codon optimized multi-epitope vaccine antigens was expressed and affinity purified using the E. coli expression system. Further the T cell epitope presentation assay using the recombinant multi-epitope constructs and the T cell epitope predicted and identified in this study have not been investigated. Multi-epitope vaccine construct encompassing predicted B- and T-cell epitopes may help to generate long-term immune responses against rotavirus. The computational findings reported in this study may provide information in developing epitope-based vaccine and diagnostic assay for rotavirus-led diarrhea in children's.

Performance of molecular and serologic tests for the diagnosis of scrub typhus

Diagnosis of scrub typhus, caused by the bacterium Orientia tsutsugamushi, is challenging because of the overlap of its non-specific symptoms with other infections coupled with the lack of sufficient data on the performance of diagnostic tests. Early diagnosis of scrub typhus is crucial to improve outcomes and this study evaluates the diagnostic performance of various tests. The present study aims at assessing the accuracy of various rapid diagnostic tests, serologic tests, and nucleic acid amplification methods on well-characterized patient samples. Adult patients with acute febrile illness and manifestations suggestive of scrub typhus confirmed by positive PCR in the blood, eschar or tissue were characterized as cases. Patients with acute febrile illness and a confirmed alternate etiology such as culture-confirmed typhoid, smear/PCR positive for malaria, PCR/NS1 antigen positive for dengue, PCR positive for influenza, PCR/MAT positive for leptospirosis, PCR positive for spotted fever were characterized as controls with other infections. The healthy controls consisted of subjects from the same geographic region. We performed the following tests on blood samples for scrub typhus and calculated the sensitivity, specificity, positive predictive value, and negative predictive value: (1) Quantitative real time PCR using 47kDa gene (qPCR); (2) Conventional PCR using 56kDa gene (cPCR); (3) Loop-mediated isothermal amplification assay (LAMP assay); (4) Immunofluorescence assay (IFA); (5) Enzyme-linked immunosorbent assay (ELISA); (6) Weil-Felix test(WF test); and (7) Immunochromatographic Rapid Diagnostic Test (RDT).Among the 316 participants, 158 had confirmed scrub typhus (cases) and 158 were controls. ELISA and RDT detecting Orientia tsutsugamushi specific IgM antibodies had excellent discriminative potential with sensitivities and specificities of 92%, 94% and 92%, 92% respectively. The sensitivity and specificity of IFA were found to be 95% and 74% respectively. IgM serology had a false positivity rate of 8% with other acute febrile illnesses such as dengue, leptospirosis and spotted fever due to the nonspecific binding of the pentavalent IgM. LAMP assay had 91.7% sensitivity and 77.2% specificity while qPCR provided excellent sensitivity (97%) and perfect specificity. In conclusion, ELISA and RDT detecting Orientia tsutsugamushi specific IgM antibodies have excellent sensitivity and specificity while the accuracy of IFA is suboptimal for the diagnosis of scrub typhus. Given its perfect specificity and superior sensitivity, qPCR is preferred for diagnostic confirmation in reference laboratories particularly for diagnosis of early disease with less than 7 days duration. This study provides a comprehensive evaluation of all currently available diagnostic tests for scrub typhus.

Clinical management of COVID-19

The novel coronavirus disease 2019 (COVID-19) with its early origin from Wuhan city in China has evolved into a global pandemic. Maximal precautionary measures and resources have been put forward by most nations in war footing to mitigate transmission and decrease fatality rates. This article was aimed to review the evidence on clinical management and to deal with the identification of high-risk groups, warning signs, appropriate investigations, proper sample collection for confirmation, general and specific treatment measures, strategies as well as infection control in the healthcare settings. Advanced age, cardiovascular disease, diabetes, hypertension and cancer have been found to be the risk factors for severe disease. Fever lasting for >five days with tachypnoea, tachycardia or hypotension are indications for urgent attention and hospitalization in a patient with suspected COVID-19. At present, reverse transcription-polymerase chain reaction (RT-PCR) from the upper respiratory tract samples is the diagnostic test of choice. While many drugs have shown in vitro activity against severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), there are insufficient clinical data to promote or dissuade their usage. Among the currently available drugs, hydroxychloroquine and lopinavir/ritonavir may be considered for patients with severe COVID-19 infection, awaiting further clinical trials. Stringent droplet and contact precautions will protect healthcare workers against most clinical exposures to COVID-19.

Treatment outcomes with daily self-administered treatment and thrice-weekly directly-observed treatment in two cohorts of newly-diagnosed, sputum-positive adults with pulmonary tuberculosis

BACKGROUND

The Revised National Tuberculosis Control Program (RNTCP) envisages shifting from thrice-weekly to a daily anti-tuberculosis treatment (ATT) regimen. The potential merits and demerits of both regimens continue to be debated.

METHODS

This retrospective study compared treatment outcomes in 191 HIV-negative, newly diagnosed, sputum-positive adults with pulmonary tuberculosis from Vellore district of Tamil Nadu who were treated at a private medical college during 2009 to 2012 with intermittent Directly Observed Treatment Short Course (intermittent DOTS cohort, n=132) or who opted for daily Self-Administered Treatment (daily SAT cohort, n=59). Treatment outcomes obtained from medical records were supplemented by interviews with consenting, traceable patients.

RESULTS

The rates for the RNTCP-recommended sputum smear examinations were suboptimal (42% for daily SAT and 72% for intermittent DOTS). However, treatment success with daily SAT and intermittent DOTS (76.2% vs. 70.4%); default (11.9% vs. 18.2%); death (6.8% vs. 5.3%); treatment failure (5.1% vs. 4.6%); and relapse (0% vs. 1.5%) did not significantly differ.

CONCLUSIONS

While evaluable treatment outcomes were not significantly different with daily SAT and intermittent DOTS, rates for timely smear examinations and for treatment success were lower, and for default higher, in both cohorts than comparable RNTCP data from Vellore district. Further strengthening of RNTCP facilities within private medical colleges and regular, real-time audits of performance and outcomes are needed if daily ATT regimen under the RNTCP is to succeed.

1655. Performance of Molecular and Serologic Tests for the Diagnosis of Scrub Typhus

Background

Diagnosis of scrub typhus, caused by the bacterium Orientia tsutsugamushi, is challenging because of the overlap of its nonspecific symptoms with other infections coupled with the lack of sufficient data on the performance of diagnostic tests. Early diagnosis of scrub typhus is crucial to improve outcomes and this study evaluated the diagnostic performance of various tests.

Methods

Adult patients with acute febrile illness and manifestations suggestive of scrub typhus confirmed by positive PCR in the blood or eschar were characterized as cases. Patients with acute febrile illness and a confirmed alternate etiology such as culture-confirmed typhoid, smear/PCR positive for malaria, PCR/NS1 antigen positive for dengue, PCR positive for influenza, PCR/MAT positive for leptospirosis, PCR positive for spotted fever were characterized as controls with other infections. The healthy controls consisted of subjects from the same geographic region. We performed the following tests on blood samples for scrub typhus and calculated the sensitivity, specificity, positive predictive value, and negative predictive value: (1) Quantitative PCR using 47 kDa gene (qPCR); (2) Conventional PCR using 56kDa gene (cPCR); (3) Loop-mediated isothermal amplification assay (LAMP assay); (4) Immunofluorescence assay (IFA); (5) Enzyme-linked immunosorbent assay (ELISA); (6) Weil–Felix test (WF test); and (7) Immunochromatographic Rapid Diagnostic Test (RDT).

Results

Among the 302 participants, 152 had confirmed scrub typhus (cases) and 150 were controls. ELISA and RDT detecting IgM antibodies had excellent discriminative potential with sensitivities and specificities of 94%, 93% and 92%, 93%, respectively. False-positive IgM serology was observed with spotted fever and leptospirosis. The sensitivity and specificity of IFA were found to be 80% and 85%, respectively. qPCR exhibited excellent sensitivity (96%) and perfect specificity.

Conclusion

ELISA and RDT detecting IgM antibodies have excellent sensitivity and specificity while the sensitivity of IFA is suboptimal for the diagnosis of scrub typhus. Given its perfect specificity and superior sensitivity, qPCR is preferred for diagnostic confirmation in reference laboratories.

Disclosures

All authors: No reported disclosures.

Clinical Manifestations, Antimicrobial Drug Susceptibility Patterns, and Outcomes in Melioidosis Cases, India

We studied the clinical manifestations and outcomes of 114 patients with culture-confirmed melioidosis treated at a tertiary hospital in southern India. Diabetes mellitus is the main risk factor, and chronic melioidosis mimicking tuberculosis was more common than acute disease. Septicemia and respiratory involvement were associated with poor outcomes.

Serum siderocalin levels in patients with tuberculosis and HIV infection

OBJECTIVES

Mycobacterium tuberculosis produces high-affinity siderophores that play essential roles in iron acquisition and tuberculosis (TB) pathogenesis. In response, host cells secrete a siderophore-binding protein, siderocalin, to limit the bacteria's access to iron. The objective of the present study was to evaluate the levels of siderocalin in patients with TB with or without HIV infection compared to controls.

METHODS

Siderocalin levels were tested using a neutrophil gelatinase-associated lipocalin (NGAL) ELISA kit in four populations: HIV-infected patients with TB (HIV^pos, TB^pos), non-HIV-infected patients with TB (HIV^neg, TB^pos), HIV-infected patients without TB (HIV^pos, TB^neg), and healthy controls (HIV^neg, TB^neg).

RESULTS

Serum siderocalin levels were significantly elevated in patients with TB regardless of their HIV status (HIV^neg, TB^pos 920 (480-1050) pg/ml; HIV^pos, TB^pos 494 (166-1050) pg/ml), whereas lower levels of siderocalin were seen in HIV-positive patients (HIV^pos, TB^neg 268 (77-937) pg/ml; HIV^neg, TB^neg 453 (193-994) pg/ml).

CONCLUSIONS

The results indicate that active TB leads to an up-regulation of serum siderocalin regardless of HIV status, whereas HIV infection leads to a down-regulation of serum siderocalin levels in both TB-negative and TB-positive individuals. Further studies are needed to evaluate siderocalin as a potential marker of active TB and to clarify its role in the pathogenesis of HIV-associated TB.

Clinical spectrum, susceptibility profile, treatment and outcome of culture-confirmed brucellosis from South India

Brucellosis, a common zoonosis, is under reported in India despite its endemicity and increased exposure to livestock among the population. This study was conducted to determine the clinical manifestations, antibiotic susceptibility pattern, treatment and outcome of culture confirmed brucellosis. Adult patients with culture confirmed brucellosis who presented to a large teaching hospital in South India between 2009 and 2015 were included. A diagnosis of brucellosis was confirmed on automated culture. Clinical profile, laboratory parameters, drug susceptibility, treatment and outcome were documented by reviewing the medical records. The cohort comprised of 22 patients with mean ± SD age of 42 ± 13 years. Twenty one (95.5%) was male. Thirteen (59%) patients were from rural area and risk of acquisition of brucellosis including occupational exposure or consumption of unpasteurized milk was evident in 16 (72.7%) patients. The mean duration of symptoms before presentation was 54.5 ± 52 days. The commonest clinical presentation was prolonged fever without a definite focus in 18 patients (82%), whereas 2 (9%) patients had osteoarticular involvement and one patient (4.5%) each had genital involvement and endocarditis. Eighteen patients (82%) with uncomplicated brucellosis were treated with aminoglycoside and doxycycline for 6 weeks. There was no relapse or mortality at 18 ± 9 months of follow up. Brucellosis in this cohort had acute or subacute presentation with prolonged fever and bacteremia. High index of clinical suspicion based on significant epidemiological history along with automated blood culture improves the efficiency of diagnosis. Cure with lack of relapse among these cases suggests a combination therapy with doxycycline and aminoglycoside is highly effective for the treatment.

BK virus characterisation among HIV-1-Infected individuals and its association with immunosuppression

Purpose

BK virus (BKV) is an opportunistic pathogen which causes significant morbidity and mortality in individuals who are immunodeficient. We aimed to quantitate and characterise BKV and to correlate with the degree of immunosuppression among human immunodeficiency virus (HIV)-1-infected individuals.

Methods

BKV DNA detection was carried out using an in-house quantitative real-time polymerase chain reaction on paired whole-blood and urine samples collected from 187 antiretroviral therapy (ART)-naïve HIV-1-infected individuals and 93 healthy individuals who served as controls. Sequencing was performed for a proportion of high BK viral load (VL) samples to observe non-coding control region (NCCR) rearrangements.

Results

BKV positivity in urine was 25.6% among HIV-infected individuals and 10.7% in control individuals (P = 0.03). The BK VL showed a significant negative correlation with CD4+ T-cell counts, a positive correlation with WHO clinical staging and no significant correlation with HIV-1 VL. Of 42 BKVs from urine samples sequenced, two showed rearrangements without clinically severe disease or high VL. Their NCCR and VP1 sequence-based genotyping revealed genotype I. In a small subset of individuals (n = 8) on ART who were being followed up, six individuals showed either decrease or complete clearance of virus with ART.

Conclusion

There was a higher frequency of BK viruria in HIV-1-infected individuals than among healthy controls and the positivity correlated with the degree of immunosuppression. There was no association of high VL with NCCR rearrangements in urine.

Melioidosis in South Asia (India, Nepal, Pakistan, Bhutan and Afghanistan)

Despite the fact that South Asia is predicted to have the highest number of cases worldwide, melioidosis is a little-known entity in South Asian countries. It has never been heard of by the majority of doctors and has as yet failed to gain the attention of national Ministries of Health and country offices of the World Health Organization (WHO). Although a few centers are diagnosing increasing numbers of cases, and the mortality documented from these institutions is relatively high (nearly 20%), the true burden of the disease remains unknown. In India, most cases have been reported from southwestern coastal Karnataka and northeastern Tamil Nadu, although this probably simply reflects the presence of centers of excellence and researchers with an interest in the disease. As elsewhere, the majority of cases have type 2 diabetes mellitus and occupational exposure to the environment. Most present with community-acquired pneumonia and/or bacteremia, especially during heavy rainfall. The high seropositivity rate (29%) in Karnataka and isolation of B. pseudomallei from the environment in Tamil Nadu and Kerala confirm India as melioidosis-endemic, although the full extent of the distribution of the organism across the country is unknown. There are limited molecular epidemiological data, but, thus far, the majority of Indian isolates have appeared distinct from those from South East Asia and Australia. Among other South Asian countries, Sri Lanka and Bangladesh are known to be melioidosis-endemic, but there are no cases that have conclusively proved to have been acquired in Nepal, Bhutan, Afghanistan or Pakistan. There are no surveillance systems in place for melioidosis in South Asian countries. However, over the past two years, researchers at the Center for Emerging and Tropical Diseases of Kasturba Medical College, University of Manipal, have established the Indian Melioidosis Research Forum (IMRF), held the first South Asian Melioidosis Congress, and have been working to connect researchers, microbiologists and physicians in India and elsewhere in South Asia to raise awareness through training initiatives, the media, workshops, and conferences, with the hope that more patients with melioidosis will be diagnosed and treated appropriately. However, much more work needs to be done before we will know the true burden and distribution of melioidosis across South Asia.

Kinetics of IgM and IgG antibodies after scrub typhus infection and the clinical implications

•

The kinetics of IgM and IgG post scrub typhus infection remain elusive.

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Scrub typhus patients were followed up to study antibody kinetics.

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IgM remained above the threshold for 12 months.

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IgG reached a peak at 10 months and remained above the threshold for 36 months.

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Paired IgM samples are required for accurate diagnosis.

Objectives

The serological detection of IgM antibodies is the most widely used test to diagnose scrub typhus infection. However, the kinetics of IgM and IgG antibodies post-infection remain elusive, which could contribute to false positivity. The objective of this study was to document the nature of the evolution of these antibody titres after infection.

Methods

Adult patients previously confirmed to have scrub typhus by IgM ELISA, positive PCR, or both, were included in this cross-sectional study. The levels of IgM and IgG antibodies in serum samples were tested using an ELISA and the distribution curve was plotted.

Results

Two hundred and three patients were included in this study. Post-infection serum sampling was done between 1 month and 46 months after documented infection. IgM levels declined gradually but remained elevated above the diagnostic cut-off for up to 12 months post-infection. However, IgG levels continued to rise reaching a peak at 10 months, followed by a gradual decline over several months. In the majority of cases, the IgG levels remained above the cut-off threshold for more than 36 months.

Conclusions

Clinicians need to be cautious in using a single serum sample for the detection of IgM to diagnose scrub typhus, as it remains elevated for up to 12 months after the infection, whereas the serum IgG level could be used as an indicator of past infection.

Spectrum of cardiac manifestations and its relationship to outcomes in patients admitted with scrub typhus infection

AIM

To study the spectrum of cardiac manifestations in scrub typhus infection and assess its relationship to outcomes.

METHODS

Demographic data, electrocardiographic (ECG) changes, left ventricular (LV) systolic and diastolic function, myocardial injury (defined as troponin T > 14 pg/mL), and pericardial effusion were documented. Myocarditis was diagnosed when myocardial injury was associated with global LV systolic dysfunction. The relationship between myocarditis and outcomes was assessed using logistic regression analysis and expressed as odds ratio (OR) with 95%CI.

RESULTS

The cohort (n = 81; 35 males) aged 49.4 ± 16.1 years (mean, SD) presented 8.1 ± 3.1 d after symptom onset. The APACHE-II score was 15.7 ± 7.0. Forty-eight (59%) patients were ventilated, and 46 (56%) required vasoactive agents. Mortality was 9.9%. ECG changes were non-specific; sinus tachycardia was the most common finding. Myocardial injury was evident in 61.7% of patients and LV systolic dysfunction in 30.9%. A diagnosis of myocarditis was made in 12.3%. In addition, seven patients with regional wall motion abnormalities had LV systolic dysfunction and elevated cardiac enzymes. Mild diastolic dysfunction was observed in 18 (22%) patients. Mild to moderate pericardial effusion was seen in 51%. On multivariate logistic regression analysis, patients with myocarditis tended to be older (OR = 1.04, 95%CI: 0.99-1.09), had shorter symptom duration (OR = 0.69, 95%CI: 0.49-0.98), and tended to stay longer in hospital (OR = 1.17, 95%CI: 0.98-1.40). Myocarditis was not associated with increased mortality.

CONCLUSION

In scrub typhus infection, cardiac manifestations are frequent and associated with increased morbidity but not mortality.

Case Report: Failure of Therapeutic Coma in Rabies Encephalitis

Rabies encephalitis is a fulminant, almost universally fatal infection involving the central nervous system. A unique treatment protocol, including anti-exicitotoxic therapy and induced coma was credited with the survival of a vaccinated teenager with bat rabies encephalitis in 2005. However, multiple efforts to replicate this expensive and intense protocol have not been successful. In this article, we report the failure of the protocol in Indian patients with canine-acquired rabies and elucidate the potential explanations for the failure of the protocol in our patients.

Issues in antifungal stewardship: an opportunity that should not be lost

Many countries have observed an increase in the incidence of invasive fungal infections (IFIs) over the past two decades with emergence of new risk factors and isolation of new fungal pathogens. Early diagnosis and appropriate antifungal treatment remain the cornerstones of successful outcomes. However, due to non-specific clinical presentations and limited availability of rapid diagnostic tests, in more than half of cases antifungal treatment is inappropriate. As a result, the emergence of antifungal resistance both in yeasts and mycelial fungi is becoming increasingly common. The Delhi Chapter of the Indian Association of Medical Microbiologists (IAMM-DC) organized a 1 day workshop in collaboration with BSAC on 10 December 2015 in New Delhi to design a road map towards the development of a robust antifungal stewardship programme in the context of conditions in India. The workshop aimed at developing a road map for optimizing better outcomes in patients with IFIs while minimizing unintended consequences of antifungal use, ultimately leading to reduced healthcare costs and prevention development of resistance to antifungals. The workshop was a conclave of all stakeholders, eminent experts from India and the UK, including clinical microbiologists, critical care specialists and infectious disease physicians. Various issues in managing IFIs were discussed, including epidemiology, diagnostic and therapeutic algorithms in different healthcare settings. At the end of the deliberations, a consensus opinion and key messages were formulated, outlining a step-by-step approach to tackling the growing incidence of IFIs and antifungal resistance, particularly in the Indian scenario.

Invasive fungal infection following chemotherapy for acute myeloid leukaemia-Experience from a developing country

The incidence of invasive fungal infections (IFI) is believed to be higher in patients with acute myeloid leukaemia (AML) undergoing chemotherapy in non-HEPA-filtered rooms. The aim of this study is to review the incidence of IFI in a large cohort of patients with AML treated at a single centre in India. Two hundred and twenty-two patients with AML treated with either induction chemotherapy or salvage chemotherapy between 2008 and 2013 were studied retrospectively. IFI was defined as per the revised EORTC-MSG criteria. Data on type of chemotherapy, prophylactic strategies, engraftment (ANC>500), the presence of IFI and survival were collected. IFI was diagnosed in 86 patients (38.7%) with proven IFI in 12 (5.4%). Use of posaconazole prophylaxis (P=.001) was the only factor associated with reduced incidence of IFI. Survival in patients with proven IFI was lower than those without proven IFI, but not statistically significant (59.4% vs 78.5%; P=.139). There is a high incidence of IFI during induction chemotherapy for acute myeloid leukaemia in developing countries. Posaconazole prophylaxis was associated with a significantly lower incidence of IFI. Optimal yet cost-effective strategies for prevention and early diagnosis of IFI are required to improve survival in patients undergoing chemotherapy for AML.

Epidemiology & risk factors of scrub typhus in south India

Background & objectives:

Scrub typhus is a major public health threat in South and Southeastern Asian countries including India. Understanding local patterns of disease and factors that place individuals at risk is pivotal to future preventive measures against scrub typhus. The primary aim of this study was to identify specific epidemiological and geographical factors associated with an increased risk of developing scrub typhus in this region.

Methods:

We mapped 709 patients from Tamil Nadu, Andhra Pradesh and Telangana who were admitted to the Christian Medical College (CMC) Hospital, Vellore, Tamil Nadu, India, for the period 2006-2011, assessed seasonality using monthly counts of scrub typhus cases, and conducted a case-control study among a subset of patients residing in Vellore.

Results:

The geographic distribution of cases at CMC Hospital clusters around the Tamil Nadu-Andhra Pradesh border. However, distinct hotspots clearly exist distal to this area, near Madurai and the coast in Tamil Nadu, and in the Northeast of Andhra Pradesh. Seasonally, the highest numbers of cases were observed in the cooler months of the year, i.e. September to January. In the case-control analysis, cases were more likely to be agricultural laborers (OR 1.79, 95% CI 1.01 - 3.15), not wear a shirt at home (OR 4.23, 95% CI 1.12 - 16.3), live in houses adjacent to bushes or shrubs (OR 1.95, 95% CI 1.08 - 3.53), and live in a single room home (OR 1.75, 95% CI 1.02 - 3.01). On binary logistic regression, the first three of these variables were statistically significant.

Interpretation & conclusions:

With the growing number of cases detected in India, scrub typhus is fast emerging as a public health threat and further research to protect the population from this deadly infection is essential. Health education campaigns focusing on the agricultural workers of Southern India, especially during the cooler months of the year, can serve as an important public health measure to control infection.

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

<p class="ABS"><span class="ABS_Bold-Italic" lang="en-GB">Background &amp; Materials and Methods:</span> In scrub typhus (ST) the correlation of disease severity to the presence or absence of eschar is not known. We describe the differences between patients with an eschar and those without. <span class="ABS_Bold-Italic" lang="en-GB">Results:</span> In the 193 patients, 105 (56%) had an eschar. Patients with an eschar had a higher incidence of renal failure (18.1% vs. 5.7%; P = 0.01), respiratory system involvement (30.5% vs. 13.6%; P = 0.01) and cardiovascular system (CVS) involvement (21.9% vs. 10.2%; P = 0.03). Involvement of the central nervous system, hematological system and gastro-intestinal tract were not statistically significant between the two groups. ST patients with an eschar had significantly higher requirement for noninvasive ventilation (9.1% vs. 1.9%; P = 0.04). Requirement of invasive ventilation and inotropic supports were the same in both groups. <span class="ABS_Bold-Italic" lang="en-GB">C</span><span class="ABS_Bold-Italic" lang="en-GB">onclusion:</span> The presence of an eschar in patients with ST is associated with a higher incidence of renal dysfunction, CVS and respiratory system involvement and a greater requirement of noninvasive ventilatory support.</p>

Prevalence and risk factors for scrub typhus in South India

OBJECTIVE

To determine the prevalence and risk factors of scrub typhus in Tamil Nadu, South India.

METHODS

We performed a clustered seroprevalence study of the areas around Vellore. All participants completed a risk factor survey, with seropositive and seronegative participants acting as cases and controls, respectively, in a risk factor analysis. After univariate analysis, variables found to be significant underwent multivariate analysis.

RESULTS

Of 721 people participating in this study, 31.8% tested seropositive. By univariate analysis, after accounting for clustering, having a house that was clustered with other houses, having a fewer rooms in a house, having fewer people living in a household, defecating outside, female sex, age >60 years, shorter height, lower weight, smaller body mass index and smaller mid-upper arm circumference were found to be significantly associated with seropositivity. After multivariate regression modelling, living in a house clustered with other houses, female sex and age >60 years were significantly associated with scrub typhus exposure.

CONCLUSIONS

Overall, scrub typhus is much more common than previously thought. Previously described individual environmental and habitual risk factors seem to have less importance in South India, perhaps because of the overall scrub typhus-conducive nature of the environment in this region.

Posaconazole: an emerging therapeutic option for invasive rhino-orbito-cerebral mucormycosis

Posaconazole has significant activity against the Mucormycetes. However, data are limited on the clinical efficacy of posaconazole for treating rhino-orbito-cerebral mucormycosis (ROCM). The aim of this study is to assess the efficacy and safety of posaconazole in patients with ROCM. We included 12 consecutive adult patients admitted with ROCM and treated with posaconazole between January 2010 and February 2015. The main outcome of the study was the overall success rate (i.e. either complete or partial response) at the end of treatment. We also assessed serum posaconazole concentrations in a subgroup of patients. Of the 12 patients who received posaconazole, eight patients (66.6%) had complete resolution with median follow-up of 6.5 months (range 2-24 months). Two patients (16.6%) had significant reduction of disease and two (16.6%) had marked residual disease on follow-up. Uncontrolled diabetes was the predisposing factor in all except one patient. One patient developed diarrhoea on posaconazole, which settled without discontinuation of the drug. Posaconazole appears to be a safe and effective antifungal agent in diabetic patients with ROCM, especially in those who have toxicity with polyene therapy.

Nuclear Imaging for Classic Fever of Unknown Origin: Meta-Analysis

Several studies have assessed nuclear imaging tests for localizing the source of fever in patients with classic fever of unknown origin (FUO); however, the role of these tests in clinical practice remains unclear. We systematically reviewed the test performance, diagnostic yield, and management decision impact of nuclear imaging tests in patients with classic FUO.

METHODS

We searched PubMed, Scopus, and other databases through October 31, 2015, to identify studies reporting on the diagnostic accuracy or impact on diagnosis and management decisions of ¹⁸F-FDG PET alone or integrated with CT (¹⁸F-FDG PET/CT), gallium scintigraphy, or leukocyte scintigraphy. Two reviewers extracted data. We quantitatively synthesized test performance and diagnostic yield and descriptively analyzed evidence about the impact on management decisions.

RESULTS

We included 42 studies with 2,058 patients. Studies were heterogeneous and had methodologic limitations. Diagnostic yield was higher in studies with higher prevalence of neoplasms and infections. Nonneoplastic causes, such as adult-onset Still's disease and polymyalgia rheumatica, were less successfully localized. Indirect evidence suggested that ¹⁸F-FDG PET/CT had the best test performance and diagnostic yield among the 4 imaging tests; summary sensitivity was 0.86 (95% confidence interval [CI], 0.81-0.90), specificity 0.52 (95% CI, 0.36-0.67), and diagnostic yield 0.58 (95% CI, 0.51-0.64). Evidence on direct comparisons of alternative imaging modalities or on the impact of tests on management decisions was limited.

CONCLUSION

Nuclear imaging tests, particularly ¹⁸F-FDG PET/CT, can be useful in identifying the source of fever in patients with classic FUO. The contribution of nuclear imaging may be limited in clinical settings in which infective and neoplastic causes are less common. Studies using standardized diagnostic algorithms are needed to determine the optimal timing for testing and to assess the impact of tests on management decisions and patient-relevant outcomes.

Differential diagnosis of scrub typhus meningitis from bacterial meningitis using clinical and laboratory features

BACKGROUND

Central nervous system (CNS) involvement in the form of meningitis or meningoencephalitis is common in scrub typhus. As specific laboratory methods remain inadequate or inaccessible in developing countries, prompt diagnosis is often difficult.

AIM

To identify the clinical and laboratory parameters that may help in differentiating scrub typhus meningitis from bacterial meningitis.

SETTING AND DESIGN

This is a cross-sectional analysis of adult patients admitted with scrub typhus and bacterial meningitis to a tertiary care teaching institute in South India.

MATERIALS AND METHODS

A comparison of clinical and laboratory features of 25 patients admitted with meningitis to a university teaching hospital during a 15-month period was made. These patients had meningitis diagnosed based on abnormal cerebrospinal fluid (CSF) analysis with either positive IgM scrub typhus ELISA serology (n =16) or with CSF culture isolating bacteria known to cause bacterial meningitis (n =9). The clinical and laboratory features of the patients with scrub typhus meningitis and bacterial meningitis were compared.

RESULTS

The mean age was similar in the scrub typhus and bacterial meningitis groups (44.0 ± 18.5 years vs. 46.3 ± 23.0 years). Features at admission predictive of a diagnosis of scrub typhus meningitis were duration of fever at presentation >5 days (8.4 ± 3.5 days vs. 3.3 ± 4.2 days, P < 0.001), CSF white cell count of a lesser magnitude (83.2 ± 83.0 cells/cumm vs. 690.2 + 753.8 cells/cumm, P < 0.001), CSF lymphocyte proportion >50% (83.9 ± 12.5% vs. 24.8 ± 17.5% P < 0.001), and alanine aminotransferase (ALT) elevation more than 60 IU (112.5 ± 80.6 IU vs. 35 ± 21.4 IU, P =0.02).

CONCLUSION

This study suggests that clinical features, including the duration of fever and laboratory parameters such as CSF pleocytosis, CSF lymphocyte proportion >50%, and ALT values are helpful in differentiating scrub typhus from bacterial meningitis.

DHR-ICMR Guidelines for diagnosis & management of Rickettsial diseases in India

Rickettsial diseases, caused by a variety of obligate intracellular, Gram-negative bacteria from the genera Rickettsia, Orientia, Ehrlichia, Neorickettsia, Neoehrlichia, and Anaplasma, belonging to the Alphaproteobacteria, are considered some of the most covert emerging and re-emerging diseases and are being increasingly recognized. Among the major groups of rickettsioses, commonly reported diseases in India are scrub typhus, murine flea-borne typhus, Indian tick typhus and Q fever. Rickettsial infections are generally incapacitating and difficult to diagnose; untreated cases have case fatality rates as high as 30-45 per cent with multiple organ dysfunction, if not promptly diagnosed and appropriately treated. The vast variability and non-specific presentation of this infection have often made it difficult to diagnose clinically. Prompt antibiotic therapy shortens the course of the disease, lowers the risk of complications and in turn reduces morbidity and mortality due to rickettsial diseases. There is a distinct need for physicians and health care workers at all levels of care in India to be aware of the clinical features, available diagnostic tests and their interpretation, and the therapy of these infections. Therefore, a Task Force was constituted by the Indian Council of Medical Research (ICMR) to formulate guidelines for diagnosis and management of rickettsial diseases. These guidelines include presenting manifestations, case definition, laboratory criteria (specific and supportive investigations) and treatment.

Acute Undifferentiated Febrile Illness in Patients Presenting to a Tertiary Care Hospital in South India: Clinical Spectrum and Outcome

Background:

Acute undifferentiated febrile illness (AUFI) may have similar clinical presentation, and the etiology is varied and region specific.

Materials and Methods:

This prospective observational study was conducted in a tertiary hospital in South India. All adult patients presenting with AUFI of 3–14 days duration were evaluated for etiology, and the differences in presentation and outcome were analyzed.

Results:

The study cohort included 1258 patients. A microbiological cause was identified in 82.5% of our patients. Scrub typhus was the most common cause of AUFI (35.9%) followed by dengue (30.6%), malaria (10.4%), enteric fever (3.7%), and leptospirosis (0.6%). Both scrub typhus and dengue fever peaked during the monsoon season and the cooler months, whereas no seasonality was observed with enteric fever and malaria. The mean time to presentation was longer in enteric fever (9.9 [4.7] days) and scrub typhus (8.2 [3.2] days). Bleeding manifestations were seen in 7.7% of patients, mostly associated with dengue (14%), scrub typhus (4.2%), and malaria (4.6%). The requirement of supplemental oxygen, invasive ventilation, and inotropes was higher in scrub typhus, leptospirosis, and malaria. The overall mortality rate was 3.3% and was highest with scrub typhus (4.6%) followed by dengue fever (2.3%). Significant clinical predictors of scrub typhus were breathlessness (odds ratio [OR]: 4.96; 95% confidence interval [CI]: 3.38–7.3), total whole blood cell count >10,000 cells/mm³ (OR: 2.31; 95% CI: 1.64–3.24), serum albumin <3.5 g % (OR: 2.32; 95% CI: 1.68–3.2). Overt bleeding manifestations (OR: 2.98; 95% CI: 1.84–4.84), and a platelet count of <150,000 cells/mm³ (OR: 2.09; 95% CI: 1.47–2.98) were independent predictors of dengue fever.

Conclusion:

The similarity in clinical presentation and diversity of etiological agents demonstrates the complexity of diagnosis and treatment of AUFI in South India. The etiological profile will be of use in the development of rational guidelines for control and treatment of AUFI.

Molecular epidemiology and genetic diversity of Orientia tsutsugamushi from patients with scrub typhus in 3 regions of India

Clarifying local antigenic diversity is critical for development of region-specific vaccines and diagnostics.

Scrub typhus, an acute febrile illness that is widespread in the Asia-Pacific region, is caused by the bacterium Orientia tsutsugamushi, which displays high levels of antigenic variation. We conducted an investigation to identify the circulating genotypes of O. tsutsugamushi in 3 scrub typhus–endemic geographic regions of India: South India, Northern India, and Northeast India. Eschar samples collected during September 2010–August 2012 from patients with scrub typhus were subjected to 56-kDa type-specific PCR and sequencing to identify their genotypes. Kato-like strains predominated (61.5%), especially in the South and Northeast, followed by Karp-like strains (27.7%) and Gilliam and Ikeda strains (2.3% each). Neimeng-65 genotype strains were also observed in the Northeast. Clarifying the genotypic diversity of O. tsutsugamushi in India enhances knowledge of the regional diversity among circulating strains and provides potential resources for future region-specific diagnostic studies and vaccine development.

Severe scrub typhus infection: Clinical features, diagnostic challenges and management

Scrub typhus infection is an important cause of acute undifferentiated fever in South East Asia. The clinical picture is characterized by sudden onset fever with chills and non-specific symptoms that include headache, myalgia, sweating and vomiting. The presence of an eschar, in about half the patients with proven scrub typhus infection and usually seen in the axilla, groin or inguinal region, is characteristic of scrub typhus. Common laboratory findings are elevated liver transaminases, thrombocytopenia and leukocytosis. About a third of patients admitted to hospital with scrub typhus infection have evidence of organ dysfunction that may include respiratory failure, circulatory shock, mild renal or hepatic dysfunction, central nervous system involvement or hematological abnormalities. Since the symptoms and signs are non-specific and resemble other tropical infections like malaria, enteric fever, dengue or leptospirosis, appropriate laboratory tests are necessary to confirm diagnosis. Serological assays are the mainstay of diagnosis as they are easy to perform; the reference test is the indirect immunofluorescence assay (IFA) for the detection of IgM antibodies. However in clinical practice, the enzyme-linked immuno-sorbent assay is done due to the ease of performing this test and a good sensitivity and sensitivity when compared with the IFA. Paired samples, obtained at least two weeks apart, demonstrating a ≥ 4 fold rise in titre, is necessary for confirmation of serologic diagnosis. The mainstay of treatment is the tetracycline group of antibiotics or chloramphenicol although macrolides are used alternatively. In mild cases, recovery is complete. In severe cases with multi-organ failure, mortality may be as high as 24%.

Toxicity and clinical outcomes in patients with HIV on zidovudine and tenofovir based regimens: a retrospective cohort study

BACKGROUND

Adverse drug reactions are a major concern with zidovudine/stavudine treatment regimens. The less toxic tenofovir regimen is an alternative, but is seldom considered due to the higher costs. This study compared adverse drug reactions and other clinical outcomes resulting from the use of these two treatment regimens in India.

METHODS

Baseline, clinical characteristics and follow-up outcomes were collected by chart reviews of HIV-positive adults and compared using univariate/multivariate analysis, with and without propensity score adjustments.

RESULTS

Data were collected from 129 and 92 patients on zidovudine (with lamivudine and nevirapine) and tenofovir (with emtricitabine and efavirenz) regimens, respectively. Compared to patients receiving the zidovudine regimen, patients receiving the tenofovir regimen had fewer adverse drug reactions (47%, 61/129 vs 11%, 10/92; p<0.01), requiring fewer regimen changes (36%, 47/129 vs 3%, 3/92; p0.01). With the propensity score, the zidovudine regimen had 8 times more adverse drug reactions (p<0.01). Opportunistic infections were similar between regimens without propensity score, while the zidovudine regimen had 1.2 times (p=0.63) more opportunistic infections with propensity score. Patients on the tenofovir regimen gained more weight. Increase in CD4 levels and treatment adherence (>95%) was similar across regimens.

CONCLUSIONS

Patients on a tenofovir regimen have better clinical outcomes and improved general health than patients on the zidovudine regimen.

Deregulated tyrosine-phenylalanine metabolism in pulmonary tuberculosis patients

Metabolic profiling of biofluids from tuberculosis (TB) patients would help us in understanding the disease pathophysiology and may also be useful for the development of novel diagnostics and host-directed therapy. In this pilot study we have compared the urine metabolic profiles of two groups of subjects having similar TB symptoms and categorized as active TB (ATB, n = 21) and non-TB (NTB, n = 21) based on GeneXpert test results. Silylation, gas chromatography mass spectrometry, and standard chemometric methods were employed to identify the important molecules and deregulated metabolic pathways. Eleven active TB patients were followed up on longitudinally for comparative urine metabolic profiling with healthy controls (n = 11). A set of 42 features qualified to have a variable importance parameter score of > 1.5 of a partial least-squares discriminate analysis model and fold change of > 1.5 at p value < 0.05 between ATB and NTB. Using these variables, a receiver operating characteristics curve was plotted and the area under the curve was calculated to be 0.85 (95% CI: 0.72-0.96). Several of these variables that represent norepinephrine, gentisic acid, 4-hydroxybenzoic acid, hydroquinone, and 4-hydroxyhippuric acid are part of the tyrosine-phenylalanine metabolic pathway. In the longitudinal study we observed a treatment-dependent trend in the urine metabolome of follow-up samples, and subjects declared as clinically cured showed similar metabolic profile as those of asymptomatic healthy subjects. The deregulated tyrosine-phenylalanine axis reveals a potential target for diagnostics and intervention in TB.

Septic arthritis of the temporomandibular joint caused by Aspergillus flavus infection as a complication of otitis externa

Septic arthritis of the temporomandibular joint (TMJ) is a very rare complication of otitis externa that can lead to ankylosis and destruction of the joint. We report the case of a 74-year-old man who developed aspergillosis of the TMJ following otitis externa. To the best of our knowledge, this is the first reported case of TMJ septic arthritis secondary to otitis externa caused by Aspergillus flavus. The patient was successfully managed with condylectomy, debridement, and drug treatment with voriconazole.

Scrub typhus meningitis: An under-recognized cause of aseptic meningitis in India

BACKGROUND

Central nervous system (CNS) involvement in scrub typhus is seen in up to a quarter of patients. However, the literature on cerebrospinal fluid (CSF) analysis and outcome in meningitis/meningo-encephalitis due to scrub typhus is scant.

MATERIALS AND METHODS

This retrospective study included patients who were admitted to a medical college hospital with scrub typhus meningitis/meningo-encephalitis between 2005 and 2011. The clinical and laboratory profile, details of CSF analysis and outcome were documented.

RESULTS

The study included 189 patients with meningitis/meningo-encephalitis due to scrub typhus. The mean age of the patients was 41 ± 4 years. The mean duration of fever before presentation was 9.4 ± 3 days. The common presenting complaints were headache (64.2%), nausea/vomiting (60%), altered sensorium (53.7%) and seizures (22.1%). The presence of an eschar was documented in 27.5% of the patients. The mean CSF white blood count was 80 cells/cu mm (range: 5-740). There was a clear lymphocyte predominance (mean 87.6%). The mean CSF protein level was 105 mg% (range: 13-640). The mean CSF sugar level was 63.9 mg% (range 25-350), and was less than 40 mg% in 11.1% of the cases. The case fatality rate was 5.8% (11/189). Univariate analysis showed the presence of an eschar (15.4% vs 2.2%; Odds Ratio [OR]: 8.1) and altered sensorium (9.8% vs 1.1%; OR: 9.2) to be significant predictors of mortality.

CONCLUSIONS

In endemic regions, scrub typhus should be considered in the differential diagnosis of aseptic meningitis. Modest elevation of cells in the CSF with lymphocytic pleocytosis and multi-organ involvement may indicate scrub typhus meningitis/meningo-encephalitis.

Kikuchi-fujimoto disease: clinical and laboratory characteristics and outcome

Introduction:

Kikuchi-Fujimoto disease is an uncommon disorder with worldwide distribution, characterized by fever and benign enlargement of the lymph nodes, primarily affecting young adults. Awareness about this disorder may help prevent misdiagnosis and inappropriate investigations and treatment. The objective of the study was to evaluate the clinical and laboratory characteristics of histopathologically confirmed cases of Kikuchi's disease from a tertiary care center in southern India.

Materials and Methods:

Retrospective analysis of all adult patients with histopathologically confirmed Kikuchi's disease from January 2007 to December 2011 in a 2700-bed teaching hospital in South India was done. The clinical and laboratory characteristics and outcome were analyzed.

Results:

There were 22 histopathologically confirmed cases of Kikuchi's disease over the 5-year period of this study. The mean age of the subjects’ was 29.7 years (SD 8.11) and majority were women (Male: female- 1:3.4). Apart from enlarged cervical lymph nodes, prolonged fever was the most common presenting complaint (77.3%). The major laboratory features included anemia (54.5%), increased erythrocyte sedimentation rate (31.8%), elevated alanine aminotransferase (27.2%) and elevated lactate dehydrogenase (LDH) (31.8%).

Conclusion:

Even though rare, Kikuchi's disease should be considered in the differential diagnosis of young individuals, especially women, presenting with lymphadenopathy and prolonged fever. Establishing the diagnosis histopathologically is essential to avoid inappropriate investigations and therapy.

Diagnosis of scrub typhus

Scrub typhus is an acute febrile illness that, if untreated, can result in considerable morbidity and mortality. One of the primary reasons for delays in the treatment of this potentially fatal infection is the difficulty in diagnosing the condition. Diagnosis is often complicated because of the combination of non-specific symptoms that overlap with other infections commonly found in endemic areas and the poor available diagnostics. In the majority of the endemic settings, diagnosis still relies on the Weil-Felix test, which is neither sensitive nor specific. Other methods of testing have become available, but at this time, these remain insufficient to provide the rapid point-of-care diagnostics that would be necessary to significantly change the management of this infection by providers in endemic areas. This article reviews the currently available diagnostic tools for scrub typhus and their utility in the clinical setting.

Profile of organ dysfunction and predictors of mortality in severe scrub typhus infection requiring intensive care admission

Background and Aims:

Scrub typhus, a zoonotic rickettsial infection, is an important reason for intensive care unit (ICU) admission in the Indian subcontinent. We describe the clinical profile, organ dysfunction, and predictors of mortality of severe scrub typhus infection.

Materials and Methods:

Retrospective study of patients admitted with scrub typhus infection to a tertiary care university affiliated teaching hospital in India during a 21-month period.

Results:

The cohort (n = 116) aged 40.0 ± 15.2 years (mean ± SD), presented 8.5 ± 4.4 days after symptom onset. Common symptoms included fever (100%), breathlessness (68.5%), and altered mental status (25.5%). Forty-seven (41.6%) patients had an eschar. Admission APACHE-II score was 19.6 ± 8.2. Ninety-one (85.2%) patients had dysfunction of 3 or more organ systems. Respiratory (96.6%) and hematological (86.2%) dysfunction were frequent. Mechanical ventilation was required in 102 (87.9%) patients, of whom 14 (12.1%) were solely managed with non-invasive ventilation. Thirteen patients (11.2%) required dialysis. Duration of hospital stay was 10.7 ± 9.7 days. Actual hospital mortality (24.1%) was less than predicted APACHE-II mortality (36%; 95% Confidence interval 32-41). APACHE-II score and duration of fever were independently associated with mortality on logistic regression analysis.

Conclusions:

In this cohort of severe scrub typhus infection with multi-organ dysfunction, survival was good despite high severity of illness scores. APACHE-II score and duration of fever independently predicted mortality.

Eschar in scrub typhus: a valuable clue to the diagnosis

BACKGROUND

Scrub typhus is an acute febrile illness widely prevalent in the 'tsutsugamushi triangle' region of the world. Clinical features include fever, myalgia, headache, rash, and a pathognomonic eschar. An eschar is formed by the bite of chigger mite that inoculates the causative agent of Scrub typhus Orientia tsutsugamushi. The aim of this study is to determine the most common sites of eschars over the bodies of patients with Scrub typhus.

MATERIALS AND METHODS

In a retrospective analysis, we examined a total of 418 patients who presented to Christian Medical College, Vellore between 2009 and 2012 with an acute febrile illness and an eschar on clinical examination and confirmed to have scrub typhus with a positive Scrub typhus IgM ELISA test. We studied the distribution of eschars over the bodies of 418 patients with Scrub typhus.

RESULTS

There was a significant difference in the distribution of eschars between males and females with a preponderance of the chest and abdomen (42.3%) among females and the axilla, groin and genitalia (55.8%) in males. Some unusual sites of an eschar were the cheek, ear lobe and dorsum of the feet.

CONCLUSION

The eschar is the most useful diagnostic clue in patients with acute febrile illness in areas endemic for Scrub typhus and therefore should be thoroughly examined for its presence especially over the covered areas such as the groin, genitalia, infra-mammary area and axilla.

Tropical fevers: Management guidelines

Tropical fevers were defined as infections that are prevalent in, or are unique to tropical and subtropical regions. Some of these occur throughout the year and some especially in rainy and post-rainy season. Concerned about high prevalence and morbidity and mortality caused by these infections, and overlapping clinical presentations, difficulties in arriving at specific diagnoses and need for early empiric treatment, Indian Society of Critical Care Medicine (ISCCM) constituted an expert committee to develop a consensus statement and guidelines for management of these diseases in the emergency and critical care. The committee decided to focus on most common infections on the basis of available epidemiologic data from India and overall experience of the group. These included dengue hemorrhagic fever, rickettsial infections/scrub typhus, malaria (usually falciparum), typhoid, and leptospira bacterial sepsis and common viral infections like influenza. The committee recommends a 'syndromic approach' to diagnosis and treatment of critical tropical infections and has identified five major clinical syndromes: undifferentiated fever, fever with rash / thrombocytopenia, fever with acute respiratory distress syndrome (ARDS), fever with encephalopathy and fever with multi organ dysfunction syndrome. Evidence based algorithms are presented to guide critical care specialists to choose reliable rapid diagnostic modalities and early empiric therapy based on clinical syndromes.

Scrub typhus in South India: clinical and laboratory manifestations, genetic variability, and outcome

OBJECTIVES

This study sought to document the clinical and laboratory manifestations, genetic variability, and outcomes of scrub typhus, an often severe infection caused by Orientia tsutsugamushi, in South India.

METHODS

Patients admitted to a large teaching hospital with IgM ELISA-confirmed scrub typhus were evaluated. Clinical examination with a thorough search for an eschar, laboratory testing, chest X-ray, and outcome were documented and analyzed. Additionally, a 410-bp region of the 56-kDa type-specific antigen gene of O. tsutsugamushi was sequenced and compared with isolates from other regions of Asia.

RESULTS

Most of the 154 patients evaluated presented with fever and non-specific symptoms. An eschar was found in 86 (55%) patients. Mild hepatic involvement was seen in most, with other organ involvement including respiratory, cardiovascular, and renal. Multi-organ dysfunction was noted in 59 (38.3%), and the fatality rate was 7.8%. Hypotension requiring vasoactive agents was found to be an independent predictor of mortality (p<0.001). The phylogeny of 26 samples showed 17 (65%) clustering with the Kato-like group and eight (31%) with the Karp-like group.

CONCLUSIONS

The presentation of scrub typhus can be variable, often non-specific, but with potentially severe multi-organ dysfunction. Prompt recognition is key to specific treatment and good outcomes. Further study of the circulating strains is essential for the development of a successful vaccine and sensitive point-of-care testing.

Salmonella typhi rib osteomyelitis with abscess mimicking a 'cold abscess'

Salmonella enterica serovar typhi (Salmonella typhi) causing typhoid fever is common in many parts of the world particularly in developing countries. Extra-intestinal manifestations such as osteomyelitis are rare in immunocompetent individuals. We report a case of Salmonella typhi osteomyelitis of a rib with overlying abscess mimicking a ‘cold abscess’, treatment outcomes and discuss relevant literature.

A probable case of acquired toxoplasmosis presenting as pyrexia of unknown origin in an immunocompetent individual

Disseminated toxoplasmosis presenting as a prolonged febrile illness is rare in immunocompetent individuals. We report a probable case of acquired toxoplasmosis in an immunocompetent woman who presented with fever of 6 months duration with lymphadenopathy and splenomegaly. The diagnosis was confirmed by serology and the presence of Toxoplasma gondii tachyzoites on bone marrow aspirate. The patient was successfully treated with pyrimethamine plus clindamycin.