Serological evidence for the continued presence of human rickettsioses in southern India

Spotted fever diagnosis: Experience from a South Indian center

Spotted fever (SF) is an important treatable cause of acute febrile illness (AFI) with rash and has reemerged in India. A prospective AFI with rash study was undertaken at a South Indian hospital to correlate specific clinical findings with laboratory confirmation of spotted fever. During the study period (December 2017 to May 2019), 175 patients with fever and rash were suspected to have spotted fever. Molecular assays for scrub typhus and spotted fever (47 kDa and ompA qPCR) and serology (IgM ELISA) was performed on the 96 individuals recruited. Laboratory confirmed SF cases (ompA qPCR positive) were 21, whereas laboratory supported SF cases (ompA negative but sero-positive by SF IgM ELISA) were 27. Among the 48 spotted fever (SF) cases, 70% of had maculopapular rash, 12.5% had macular rash, purpuric/petechial rash (severe rash) was seen in 8 patients (16.7%). Presence of rash on the palms and soles was associated with a relative risk (RR) of 4.36 (95% CI: 2.67-7.10; p < 0.001). Our study suggests that ompA qPCR though useful for confirming the diagnosis of spotted fever is not always positive. A positive SF IgM ELISA in febrile individuals with palmo-plantar rash supports the diagnosis of spotted fever especially when other causes of febrile rash have been excluded. Multi-centric prospective studies employing the serological reference standard, IFA (immunofluorescence assay) in addition to the assays used in this study are needed to validate these findings.

Rickettsial Infections among the Undifferentiated Febrile Patients Attending a Tertiary Care Teaching Hospital of Northern India: A Longitudinal Study

Background

Acute undifferentiated febrile illness (AUFI) is one of the most daunting challenges a physician faces in such settings. Among AUFI, rickettsial infections are most common and related infections (such as anaplasmosis, ehrlichiosis, and Q fever) which are caused by an unusual type of bacteria that can live only inside the cells of another organism. The present study was therefore planned with an objective to estimate the prevalence of rickettsial infection among patients of undifferentiated fever and to determine any association of socio-demographic characteristics with rickettsial disease.

Materials and Methods

Patients presenting with febrile illness and admitted or attending out-patient department of Sher-i-Kashmir Institute of Medical Sciences, Srinagar was approached and recruited in the study. Weil Felix Assay, enzyme-linked immunosorbent assay and indirect immunofluorescence assay were done to detect the anti-rickettsial antibodies. Serological evidence of a fourfold increase in IgG-specific antibody titer reactive with spotted fever group rickettsial antigen by indirect immunofluorescence antibody assays between paired serum specimens was considered a confirmatory diagnosis for the rickettsial disease.

Results

Most of the patients were males 61.6%, and most 46.2% were in the age group of 20 -39 years. Most of the patients, 80.8% belonged to rural areas, and 48% belonged to the upper middle (II) class of the socio-economic class according to modified Kuppuswamy scale. Of the studied participants, a majority, 47.0%, were determined undiagnosed, while 15.4% studied participants were diagnosed to have a rickettsial disease. In patients positive for typhus group, 67.8% were IgM positive, 28.5% were IgG positive, and only 3% were positive for IgM and IgG. In patients positive for Scrub Typhus Group, 32.7% were positive for IgM, and 62.0% were positive for IgG, and only 5.0% were positive for both IgM and IgG. In patients positive for spotted fever group, 36.1% were positive for IgM, and 58.5% were positive for IgG, and only 5.5% were positive for both IgM and IgG. The prevalence of rickettsial disease was found to be 11.3%.

Conclusion

Rickettsial diseases, typhoid and brucellosis, were the most prevalent diseased diagnosed among patients reporting to hospitals with undifferentiated febrile illness. Clinicians must consider rickettsial diseases as one of the differential diagnosis while treating patients with fever.

Seroprevalence trends of Scrub typhus among the febrile patients of Northern India: A prospective cross-sectional study

BACKGROUND

Rickettsial infections remain one of the most neglected and underdiagnosed tropical diseases in the developing countries. Scrub typhus can prove to an important diagnosis in pyrexia of unknown origin (PUO) patients and is transmitted by a species of trombiculid mites ("chiggers"). The disease leads to a plethora of symptoms like fever, rash, headache, nausea, abdominal pain, thrombocytopenia, etc. The current study was aimed to assess the seroprevalence as well as other demographic parameters of scrub typhus among patients diagnosed with PUO in the northern part of India.

MATERIALS AND METHODS

This study was undertaken for a period of 3 years from September 2017 to September 2020. Serum samples of suspected cases were tested for IgM Scrub typhus along with other common febrile illnesses like Malaria, typhoid, dengue, leptospirosis, chikengunya, etc. Additional testing for COVID-19 was also planned for samples received after February 2020.

RESULTS

The overall seroprevalence of Scrub typhus during the 3 year study period was noted to be 18.6% in the PUO patients. Typhoid was noted in 39.5%, malaria in 9.2%, Dengue in 13.5%, leptospirosis in 4.8%, and chikungunya in 5.3% of the patients. No cause was identified in 9.1% of the PUO cases. 3.9% of the samples were positive by RT-PCR for COVID-19. No mortality was noted in the scrub typhus positive cases.

CONCLUSION

Scrub typhus is an emerging tropical rickettsial disease in the Indian subcontinent. The present study highlights the importance of screening of PUO cases for this important infection as timely institution of simple empirical treatment can prove to be life saving in such positive cases.

Abundance & distribution of trombiculid mites & Orientia tsutsugamushi, the vectors & pathogen of scrub typhus in rodents & shrews collected from Puducherry & Tamil Nadu, India

BACKGROUND & OBJECTIVES

Human cases of scrub typhus are reported every year from Puducherry and adjoining areas in southern India. However, information on the presence of causative agent, Orientia tsutsugamushi, and its vectors is lacking. Hence, the objective of the study was to find out the vector as well as pathogen distribution in rodents and shrews present in the scrub typhus-reported areas in southern India.

METHODS

Trombiculid mites were collected by combing rats and shrews collected using Sherman traps and identified to species level following standard taxonomical keys. The serum samples of the animals were used for Weil-Felix test and the clots containing blood cells were used for DNA extraction and polymerase chain reaction (PCR).

RESULTS

A total of 181 animals comprising four rodent species and one shrew species were collected from 12 villages. High proportion of chiggers was collected from the shrew, Suncus murinus (79.1%) and Rattus rattus (47.6%). A total of 10,491 trombiculid mites belonging to nine species were collected. Leptotrombidium deliense, the known vector of scrub typhus pathogen, was the predominant species (71.0%) and the chigger (L. deliense) index was 41.1 per animal. Of the 50 animals screened for the pathogen, 28 showed agglutination against OX-K in Weil-Felix test indicating the presence of antibodies against O. tsutsugamushi, the causative agent of scrub typhus. PCR carried out with the DNA extracted from blood samples of two of the animals were positive for GroEl gene of O. tsutsugamushi.

INTERPRETATION & CONCLUSIONS

L. deliense index was well above the critical limit of chigger load, indicating that all the villages were receptive for high risk of transmission of scrub typhus to human. Pathogen positivity was higher among animals collected from villages recorded for higher chigger indices due to active transmission between the chigger mites and reservoir host animals. The results are suggestive of routine vector/pathogen surveillance at hot spots to initiate timely preventive measures.

Seroepidemiology of Spotted Fever Rickettsiosis in Uttar Pradesh: A Prospective Study

INTRODUCTION

Spotted Fever Rickettsiosis (SFR), an acute febrile illness caused by Rickettsia rickettsii, R. conorii and R. akari which is associated with considerable morbidity and mortality. SFR is one of the most covert emerging infections of the present time which is prevalent in various parts of India as shown by the increase in the number of clinically diagnosed patients in various states except Uttar Pradesh.

AIM

To diagnose SFR in clinically suspected patients using serological tests and recognition of common epidemiologic situations and clinical manifestations of SFR in the state of Uttar Pradesh.

MATERIALS AND METHODS

Patients of all age groups presented with a diagnosis of Pyrexia of Unknown Origin (PUO) from May 2013 to February 2015 were evaluated. Testing was done using a nonspecific Weil felix test followed by more specific Enzyme Linked Immunosorbent Assay (ELISA) and a gold standard Immunofluorescence Assay (IFA) test for specific IgM antibodies against Rickettsia conorii. The data was statistically analysed on Graph Pad Prism (5.0) software by using Chi-square test.

RESULTS

Of the 432 patient samples tested by non specific Weil felix test, 200 (46.29 %) samples showed titre 1:80 or more and were taken as positive. Similarly out of the 432 blood samples tested by both ELISA and IFA based test against Rickettsiaconorii IgM antibody, only 115 (26.62%) samples were found to be positive and these samples were also positive by Weil felix. The common symptoms noted were fever, hepatomegaly, thrombocytopenia, lymphadenopathy and rashes, nausea followed by icterus, cyanosis, headache, oedema and abdominal pain. Eschar was found in only four (3.4%) patients. We also found that 31 patients with SFR also had associated co-infections like typhoid, malaria, dengue and hepatitis.

CONCLUSION

Our findings demonstrated that Weil Felix test can fill in as an underlying yet not sole strategy to perceive and analyse rickettsial ailments, as it needs specificity. So, it may be used to assess the burden in the area and later on other tests like ELISA or IFA can be added, as these are more specific diagnostic tests. Further, our results also showed that if a patient tests positive for the more common endemic infections, we must test for rickettsiosis so that appropriate treatment could be administered.

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.

Malignant Mediterranean spotted fever

Fever with rash is one of the most common causes of referral to a dermatologist. A plethora of conditions need to be considered in the differential diagnosis. They may be broadly classified into infectious causes, drug reactions, and autoimmune disorders. Here we present a rare case of rickettsial fever with cardiac involvement in an elderly male patient with no comorbidities.

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.

Scrub typhus: Clinical spectrum and outcome

Background:

Scrub typhus is one of the differential diagnoses for fever with thrombocytopenia. ARDS associated with Scrub typhus has high morbidity and mortality.

Aims:

To evaluate clinical features, lab values, and outcome in patients with scrub typhus and comparison in patients with or without ARDS.

Methods:

A prospective observational study was conducted on 109 patients with febrile illness and thrombocytopenia during a period of 12 months. All 109 patients were tested with both Immune-chromatography test and Weil felix test. Patients having either Immune-chromatography test/Weil felix test positive have been included and considered as scrub typhus positive whereas negative for both Immune-chromatography and Weil felix test were excluded. Clinical features, lab parameters, and outcome were evaluated in all patients with scrub typhus. Statistical analysis used in this study was T-test.

Results:

Among 58 patients who were included (After exclusion of 51 patients among total of 109 patients) 34 patients had no ARDS and 24 patients had ARDS. The clinical feature like dyspnoea, cough, low blood pressure (MAP<65 mmHg), IVC collapsibility (by ultrasound) and laboratory parameters like decreased Hemoglobin, Hematocrit, Serum albumin, and increased serum creatinine, serum total bilirubin, SGOT, SGPT, LDH, CPK, and serum lactate were statistically significant (P < 0.0001) in scrub typhus patients group with ARDS. The higher titers of Weil-felix can be correlated with more severe form of disease according to our observation. All 34 Scrub typhus patients without ARDS recovered completely. Among 24 Scrub typhus patients with ARDS, 22 patients recovered, and 2 patients died.

Conclusion:

Scrub typhus is an important differential diagnosis in a patients having fever with thrombocytopenia. Scrub typhus associated with ARDS has high morbidity and mortality. Early diagnosis and treatment with doxycycline can prevent the occurrence of ARDS

Polyarthritis and massive small bowel bleed: An unusual combination in scrub typhus

Scrub typhus is an acute febrile illness caused by the intracellular parasite Orientia tsutsugamushi. Although most cases present with mild symptoms and signs and recover spontaneously, some cases can be severe with multi-organ dysfunction and a protracted course, which may be fatal if left untreated. Apart from fever and constitutional symptoms, atypical presentations allow this disease to mimic several common conditions. We report a case of scrub typhus in an 18-year-old male who presented with severe polyarthritis involving all large joints and a massive lower gastrointestinal bleed from ulcers in the terminal ileum, secondary to vasculitis in the small bowel. This combination of pathologies has not previously been reported in cases of scrub typhus. The patient improved following surgical intervention and specific anti-rickettsial therapy with azithromycin.

Evidence for a specific host-endosymbiont relationship between 'Rickettsia sp. genotype RF2125' and Ctenocephalides felis orientis infesting dogs in India

Background

Fleas of the genus Ctenocephalides serve as vectors for a number of rickettsial zoonoses, including Rickettsia felis. There are currently no published reports of the presence and distribution of R. felis in India, however, the ubiquitous distribution of its vector Ctenocephalides felis, makes it possible that the pathogen is endemic to the region. This study investigates the occurrence of Rickettsia spp. infection in various subspecies of C. felis infesting dogs from urban areas of Mumbai, Delhi and Rajasthan in India.

Methods

Individual fleas collected off 77 stray dogs from Mumbai, Delhi and Rajasthan were screened for Rickettsia spp. by a conventional PCR targeting the ompB gene. Further genetic characterisation of Rickettsia-positive fleas was carried out using nested PCR and phylogenetic analysis of partial DNA sequences of the gltA and ompA genes. Ctenocephalides spp. were morphologically and genetically identified by PCR targeting a fragment of cox1 gene.

Results

Overall, 56/77 fleas (72.7%), including 22/24 (91.7%) from Delhi, 32/44 (72.7%) from Mumbai and 2/9 (22.2%) from Rajasthan were positive for Rickettsia DNA at the ompB gene. Sequences of gltA fragments confirmed the amplification of Rickettsia sp. genotype RF2125. The ompA gene of Rickettsia sp. genotype RF2125 was characterised for the first time and shown 96% identical to R. felis. Three species of Ctenocephalides were identified, with the Ctenocephalides felis orientis being the dominant flea species (69/77; 89.6%) in India, followed by Ctenocephalides felis felis (8/77; 10.4%).

Conclusions

High occurrence of Rickettsia sp. genotype RF2125 in C. felis orientis and the absence of R. felis suggests a specific vector-endosymbiont adaptation and coevolution of the Rickettsia felis-like sp. within subspecies of C. felis.

Indian tick typhus presenting as Purpura fulminans

Seriously ill patients presenting with purpura fulminans, sepsis and multi-organ failure often require extensive diagnostic workup for proper diagnosis and management. Host of common infections prevalent in the tropics, e.g. malaria, dengue; other septicemic infections e.g. meningococcemia, typhoid, leptospirosis, toxic shock syndrome, scarlet fever, viral exanthems like measles, infectious mononucleosis, collagen vascular diseases (Kawasaki disease, other vasculitis) diseases, and adverse drug reactions are often kept in mind, and the index of suspicion for rickettsial illness is quite low. We present a case of Indian tick typhus presenting with purpura fulminans (retiform purpura all over the body), sepsis and multiorgan failure without lymphadenopathy and eschar, successfully treated with doxycycline and discharged home. Hence, a high index clinical suspicion and prompt administration of a simple therapy has led to successful recovery of the patient.

Clinical profile of scrub typhus in children

OBJECTIVE

To study the clinical profile and outcome of scrub typhus cases admitted in an urban referral centre.

METHODS

This descriptive study describes the clinical profile of 67 children with scrub typhus, who were admitted in an urban referral centre(ICH & HC,Chennai) during the period between October 2010 and March 2011.The diagnosis was confirmed by IgM ELISA.

RESULTS

All children presented with fever. Eschar and rash were present in 46% and 35% cases, respectively. Cough, vomiting, altered sensorium and oliguria were present in 73%,59%,58% and 43%, respectively. Hepatosplenomegaly and pallor were the commonest findings encountered in more than 80% children. Other findings were edema, lymphadenopathy and icterus.Thrombocytopenia, elevated liver enzymes and leukocytosis were seen in 77%, 64% and 49% cases, respectively. Pleural effusion, ascites, shock and respiratory failure were seen in 61%, 47%,45%,34% cases, respectively. Acute renal failure, hepatic failure, multiorgan dysfunction syndrome (MODS), meningoencephalitis and acute respiratory distress syndrome(ARDS) were seen in 10%,10%,7%,6% and 4% cases, respectively. Doxycycline and azithromycin were the antibiotics used. The overall mortality rate was 11.94%. Causes of death were shock, ARDS, acute renal failure(ARF), MODS and disseminated intravascular coagulation(DIVC).

CONCLUSIONS

When a child presents with acute febrile illness, maculopapular or erythematous rash, hepatosplenomegaly, lymphadenopathy, thrombocytopenia and features suggestive of capillary leak, diagnosis of Scrub typhus must be considered and the child should be started on empirical therapy with doxycycline or azithromycin which is life saving.

Bloodstream infection among children presenting to a general hospital outpatient clinic in urban Nepal

Background

There are limited data on the etiology and characteristics of bloodstream infections in children presenting in hospital outpatient settings in South Asia. Previous studies in Nepal have highlighted the importance of murine typhus as a cause of febrile illness in adults and enteric fever as a leading bacterial cause of fever among children admitted to hospital.

Methods

We prospectively studied a total of 1084 febrile children aged between 2 months and 14 years presenting to a general hospital outpatient department in Kathmandu Valley, Nepal, over two study periods (summer and winter). Blood from all patients was tested by conventional culture and by real-time PCR for Rickettsia typhi.

Results

Putative etiological agents for fever were identified in 164 (15%) patients. Salmonella enterica serovar Typhi (S. Typhi) was identified in 107 (10%), S. enterica serovar Paratyphi A (S. Paratyphi) in 30 (3%), Streptococcus pneumoniae in 6 (0.6%), S. enterica serovar Typhimurium in 2 (0.2%), Haemophilus influenzae type b in 1 (0.1%), and Escherichia coli in 1 (0.1%) patient. S. Typhi was the most common organism isolated from blood during both summer and winter. Twenty-two (2%) patients were PCR positive for R. typhi. No significant demographic, clinical and laboratory features distinguished culture positive enteric fever and murine typhus.

Conclusions

Salmonella infections are the leading cause of bloodstream infection among pediatric outpatients with fever in Kathmandu Valley. Extension of immunization programs against invasive bacterial disease to include the agents of enteric fever and pneumococcus could improve the health of children in Nepal.

Rickettsial diseases in central India: proposed clinical scoring system for early detection of spotted fever

OBJECTIVES

To report a series of cases of rickettsial infections from central India and to develop a clinical scoring system for its early detection.

DESIGN

Retrospective review of children hospitalized during one year period with fever without a source, and presence of one or more of the clinical features suggestive of rickettsial infection. Diagnosis of rickettsial disease was made by classical clinical features and detection of IgM antibody by ELISA. A clinical scoring system was developed to diagnose spotted fever group by using classical clinical and laboratory findings.

RESULTS

161 patients were admitted and met the inclusion criteria, 75 (45.6%) were diagnosed with rickettsial diseases. 52 (69.3%) had spotted fever group and 23 (30.7%) scrub typhus. The mortality rate with rickettsial diseases was 9%. By using proposed clinical scoring system, a score of 14 has sensitivity and specificity of 96.15% and 98.84%, respectively in making a diagnosis of spotted fever group.

CONCLUSION

Rickettsial diseases are common in the central part of India and should be included in the differential diagnosis of patients with fever of undetermined source. The proposed scoring system can be used for early detection, treatment and prevention of mortality and morbidity from spotted fever group.

Rickettsial meningoencephalitis in a child--a case report

Severe central nervous system involvement has been reported in adults with Rickettsia conorii infection but rarely in children. We report here a serologically documented case of meningoencephalitis in a child caused by spotted group R. conorii. Rickettsial infection is a relatively under-diagnosed entity in children with fever and rash, probably due to low index of suspicion and the lack of definitive diagnostic facilities. Rickettsial infections can be treated effectively with anti-microbials; if they remain undiagnosed and untreated, they are associated with significant morbidity and mortality. This differential diagnosis should be considered when a child is seen with fever and rash.

Development of a real-time PCR assay for the diagnosis of scrub typhus cases in India and evidence of the prevalence of new genotype of O. tsutsugamushi

A qualitative syber green real-time PCR with primers designed for a truncated portion of the 56kDa major outer membrane antigen gene of Orientia tsutsugamushi was used to diagnose scrub typhus from the blood or serum of suspected patients. Sixty-six blood and/or sera samples from fever cases, either with high index of suspicion for scrub typhus and/or positive by Weil-Felix test (> or = 1:160), were tested with the PCR. Specificity of the PCR was confirmed by end point melt curve analysis and sequencing of the amplicons. A nested PCR for determination of the serotypes of O. tsutsugamushi was performed on to the samples. In real-time PCR strong positive fluorescence was obtained in 73% of the suspected samples. Serotype-specific PCR amplification of some of the positive samples was indicative of the Kuroki type whereas the rest were non-responsive to this test. Sequence analyses of PCR amplicons indicated the presence of new, previously undescribed type of O. tsutsugamushi in this region. This one-step real-time PCR can be used for the detection and confirmation of scrub typhus, when used independently or in conjunction with, the Weil-Felix test, which is still the only available detection test for scrub typhus in most parts of the developing world. Elaborate studies need to be taken up to further evaluate its suitability as specific molecular tool for the diagnosis of scrub typhus and to delineate the prevalent strain types in these regions for a clear epidemiological understanding of this emerging infectious disease.

Scrub typhus in Himalayas

Himachal Pradesh state of India is situated in the outer Himalayan ranges. During the rainy season, several cases of acute febrile illness of unknown origin occurred. Orientia tsutsugamushi was identified as the causative agent by microimmunofluorescence and PCR. Two new genotypes of O. tsutsugamushi were identified in the region.

"Candidatus Rickettsia kellyi," India

We report the first laboratory-confirmed human infection due to a new rickettsial genotype in India, "Candidatus Rickettsia kellyi," in a 1-year-old boy with fever and maculopapular rash. The diagnosis was made by serologic testing, polymerase chain reaction detection, and immunohistochemical testing of the organism from a skin biopsy specimen.

Tick-borne rickettsioses around the world: emerging diseases challenging old concepts

During most of the 20th century, the epidemiology of tick-borne rickettsioses could be summarized as the occurrence of a single pathogenic rickettsia on each continent. An element of this paradigm suggested that the many other characterized and noncharacterized rickettsiae isolated from ticks were not pathogenic to humans. In this context, it was considered that relatively few tick-borne rickettsiae caused human disease. This concept was modified extensively from 1984 through 2005 by the identification of at least 11 additional rickettsial species or subspecies that cause tick-borne rickettsioses around the world. Of these agents, seven were initially isolated from ticks, often years or decades before a definitive association with human disease was established. We present here the tick-borne rickettsioses described through 2005 and focus on the epidemiological circumstances that have played a role in the emergence of the newly recognized diseases.

Case reports: scrub typhus during pregnancy in India

Scrub typhus, caused by Orientia tsutsugamushi, is a rural zoonosis endemic in the Asian Pacific region. Doxycycline and chloramphenicol, the recommended drugs for treating this infection, may not be safe during pregnancy. We report on 5 patients with scrub typhus during pregnancy who were seen in India between October 2001 and February 2002. Four of the 5 women were treated initially with ciprofloxacin. Three women had stillbirths, 1 an abortion and 1 a low birthweight baby, which suggests that ciprofloxacin should not be used for treating pregnant women and that scrub typhus leads to severe adverse effects during pregnancy. Randomized controlled trials are urgently needed to ascertain the optimal drug choice, given that currently recommended drugs are contraindicated in pregnant women.