Cases Of Typhus Research Articles

ENDEMIC IN THE PANDEMIC: MURINE TYPHUS MASKING AS COVID-19 PNEUMONIA WITH PROFOUND HYPOXEMIA

TOPIC: Chest Infections TYPE: Medical Student/Resident Case Reports INTRODUCTION: The presentation of fever, fatigue, myalgias, and acute hypoxemic respiratory failure is COVID-19 viral pneumonia until proven otherwise. However, findings like rash, photophobia, and unexplained lab abnormalities suggest an alternate diagnosis. We present a case of flea-borne (murine) typhus, causing acute illness with increasing prevalence in southern Texas and California. CASE PRESENTATION: In April 2020, a 32-year-old male presented to our emergency department (ED) with one week of fever, headache, progressive dyspnea, myalgias, and flank pain. Five days prior, COVID-19 PCR was negative;he was diagnosed with bilateral pneumonia on CT chest tomography and prescribed azithromycin. In the ED, he was found to be in acute hypoxemic respiratory failure needing high flow oxygen support prompting ICU admission. Vital demonstrated temperature of 103.4 degrees, heart rate of 130, respiratory rate of 26, and Spo2 of 96% oxygen saturation on 10L non-rebreather mask;Physical exam demonstrated dry mucous membranes, conjunctivitis, and labored respirations with accessory muscle use. Labs revealed hyponatremia, elevated liver function tests, hypoalbuminemia, thrombocytopenia, and elevated lactate dehydrogenase and procalcitonin. Repeat CT chest tomography showed posterior lower lobe opacities and concomitant ground glass opacities suggestive of atypical infection. Negative workup included two COVID-19 nasopharyngeal swabs, influenza A/B, RSV, HIV, streptococcus pneumoniae, and legionella urine antigen. He admitted recent travel to the Louisiana Gulf Coast with exposure to horses, chickens, and insect bites on the arm on further questioning. Vancomycin, ceftriaxone, and doxycycline were started on hospital day 2. A papular rash appeared on the lower back on hospital day 6. He still remained febrile and with significant hypoxemia for seven days. On day 9, Rickettsial typhus serologies returned IgM 1:512, and repeat tests confirmed both elevated IgM and IgG. The patient tapered off oxygen and was discharged home on doxycycline. DISCUSSION: Many cases of murine typhus are assumed to be a viral illness, but the clinical triad of fever, headache, and rash in endemic areas must raise suspicion. The exposure was likely insect bites (fleas), although it is not necessary, as endemic typhus has been identified in rural/suburban areas from possums, rats, or cats. In the COVID-19 pandemic, murine typhus with fever and acute hypoxemic respiratory failure was challenging to identify, but early diagnosis and treatment with tetracyclines provided a good outcome. CONCLUSIONS: The presentation of fever, headache, and rash with thrombocytopenia and transaminitis should trigger typhus workup and early treatment, which may otherwise progress to critical illness and death. REFERENCE #1: Afzal Z, Kallumadanda S, Wang F, Hemmige V, Musher D. Acute Febrile Illness and Complications Due to Murine Typhus, Texas, USA1,2. Emerg Infect Dis. 2017;23(8):1268-1273. doi:10.3201/eid2308.161861 REFERENCE #2: van der Vaart TW, van Thiel PP, Juffermans NP, van Vugt M, Geerlings SE, Grobusch MP, Goorhuis A. Severe murine typhus with pulmonary system involvement. Emerg Infect Dis. 2014 Aug;20(8):1375-7. doi: 10.3201/eid2008.131421. PMID: 25062435;PMCID: PMC4111165. DISCLOSURES: No relevant relationships by Philip Lavere, source=Web Response No relevant relationships by Dharani Kumari Narendra, source=Web Response

English

BACKGROUND Scrub typhus is a mite borne zoonotic bacterial disease caused by Orientia tsutsugamushi. It is transmitted by bite of chiggers of trombiculid mite. Clinical features generally include fever, headache, and myalgia, with or without eschar/rash. People with severe illness may develop organ failure and bleeding which can be fatal if left untreated. This study was done to detect outbreak of cases of scrub typhus in Eastern India. These mites generally live in paddy fields of forested area and people visiting those areas are generally affected. Now a days these mites migrate to urban area resulting in increased incidence of scrub typhus infection in urban area. This study was conducted in collaboration with another institute. The purpose of this study was to find out the incidence of scrub typhus in our area and the relationship between occurrence of scrub typhus and seasonal, age and sex variation. METHODS This study was carried out in our tertiary care hospital with 441 samples for a period of one year (01.01.2019 to 31.12.19). All the blood samples collected from febrile patients were subjected to Weil Felix test. If the titre is > 1 : 160; this was further confirmed by specific IgM testing. Both Weil-Felix tests and IgM scrub typhus positive tests were noted. RESULTS Out of 441 samples, 98 (22.2 %, n = 441) samples were positive for both WeilFelix and scrub typhus IgM by enzyme linked immunosorbent assay (ELISA) testing. Most of the cases were seen in males. Seasonal distribution showed higher cases in the months of September and October. CONCLUSIONS In our study, the highest numbers of scrub typhus cases were found in rural areas, during the harvesting period of July–September specially in monsoon or post monsoon period when there is abundance of mite larva. This infection is also reported high in cases among children in the age group of 1 - 14 years. Patients who tested positive for scrub typhus improved radically with doxycycline. KEYWORDS Orientia Tsutsugamushi, Scrub Typhus, IgM ELISA

Purulent diseases of the middle ear and mastoid process with typhus. According to Sverzhevsky (Med. Zhurn . 1922. № 8-9)

According to Sverzhevsky (Med. Zhurn . 1922. No. 8-9) these diseases are observed in 0.2-58% of cases of typhus. In this case, purulent inflammation of the mastoid process in the vast majority of cases is preceded by the same inflammation of the middle ear at 4-5 weeks of typhoid.

How had climate variability affected the scrub typhus incidence in South Korea?

BACKGROUND AND AIM: Climate change such as global warming unexpectedly compromised human health in particular increased incidence of infectious diseases. We aimed to investigate the long-term effects of climate variability on the scrub typhus incidence in South Korea. METHODS: Meteorological variables were conjoined with scrub typhus cases reported from 2001 to 2019 in South Korea. Generalized additive model was used to explore the non-linearity of the lagged association between meteorological variables and weekly scrub typhus incidence. Then, modified generalized linear models were used to estimate weekly incidence changes beyond the identified thresholds of mean ambient temperature and relative humidity. Further, increases in annual average temperature and the number of heatwave days were linearly regressed for scrub typhus cases from September to December. RESULTS:Mean ambient temperature and relative humidity above thresholds were linearly associated with the scrub typhus incidence with a simple lag of 15 weeks. Thresholds of mean ambient temperature and relative humidity ranged from 8.0°C to 11.6°C and from 29.7% to 65%, respectively. An increase in weekly incidence from September to December ranged from 11.2% (95% CI: 8.7, 13.8) to 35.7% (95% CI: 29.6, 42.1) per 1°C elevation in mean ambient temperature from June to August. Compared to the past 30 years’ averages, mean ambient temperature elevated and the number of annual heatwave days increased. Scrub typhus cases between September and December increased by 481 (95% CI: 377, 585) per 1°C increase in mean ambient temperature, and by 406 (95% CI: 393, 419) as the annual number of heatwave days increased. CONCLUSIONS:Mean ambient temperature elevation and relative humidity increase in the summer was associated with the increased incidence of scrub typhus in the fall. Increased annual average temperature and the number of heatwave days for the last 19 years were associated with increased scrub typhus cases in a peak period. KEYWORDS: climate change, temperature, humidity, scrub typhus, infections

Impact of Meteorological Factors and Southern Oscillation Index on Scrub Typhus Incidence in Guangzhou, Southern China, 2006-2018.

Background: Scrub typhus was epidemic in the western Pacific Ocean area and East Asia, scrub typhus epidemic in densely populated areas in southern China. To better understand the association between meteorological variables, Southern Oscillation Index (SOI), and scrub typhus incidence in Guangzhou was benefit to the control and prevention.Methodology/Principal Findings: We collected weekly data for scrub typhus cases and meteorological variables in Guangzhou, and Southern Oscillation Index from 2006 to 2018, and used the distributed lag non-linear models to evaluate the relationships between meteorological variables, SOI and scrub typhus. The median value of each variable was set as the reference. The high-risk occupations were farmer (51.10%), house worker (17.51%), and retiree (6.29%). The non-linear relationships were observed with different lag weeks. For example, when the mean temperature was 27.7°C with1-week lag, the relative risk (RR) was highest as 1.08 (95% CI: 1.01–1.17). The risk was the highest when the relative humidity was 92.0% with 9-week lag, with the RR of 1.10 (95% CI: 1.02–1.19). For aggregate rainfall, the highest RR was 1.06 (95% CI: 1.03–1.11), when it was 83.0 mm with 4-week lag. When the SOI was 19 with 11-week lag, the highest RR was 1.06 (95% CI: 1.01–1.12). Most of the extreme effects of SOI and meteorological factors on scrub typical cases were statistically significant.Conclusion/Significance: The high-risk occupations of scrub typhus in Guangzhou were farmer, house worker, and retiree. Meteorological factors and SOI played an important role in scrub typhus occurrence in Guangzhou. Non-linear relationships were observed in almost all the variables in our study. Approximately, mean temperature, and relative humidity positively correlated to the incidence of scrub typhus, on the contrary to atmospheric pressure and weekly temperature range (WTR). Aggregate rainfall and wind velocity showed an inverse-U curve, whereas the SOI appeared the bimodal distribution. These findings can be helpful to facilitate the development of the early warning system to prevent the scrub typhus.

Liver Failure, Renal Failure, and a Rash: An Unusually Severe Case of Multi-Organ Failure Due to Murine Typhus

Murine typhus is a vector-borne disease transmitted to humans via fleas and typically causes an infection hallmarked by nonspecific, mild symptoms of fever, rash, and headache. More severe diseases, while rare, can occur. We present a complicated case of murine typhus resulting in liver and renal failure.Our patient was a healthy 64-year-old Hispanic gentleman who presented to his local emergency department (ED) in Southwest Texas for fevers, chills, and myalgia progressing to dyspnea, fatigue, and jaundice. He was transferred to a Central Texas transplant hospital given concern for impending liver failure as well as acute kidney injury later requiring hemodialysis. Broad-spectrum antibiotics were narrowed to empiric doxycycline with eventual improvement in his lab values and symptoms. The return of Rickettsia typhi antibody lab values later revealed murine typhus to be the cause of his disease.

The burden of scrub typhus in India: A systematic review.

BackgroundScrub typhus, a vector-borne zoonotic infection caused by the bacteria Orientia tsutsugamushi, is one of the most common and clinically important rickettsial infections worldwide. An estimated one million cases occur annually with a high case fatality rate. Although scrub typhus is a major public health threat in India, the burden and distribution remains unclear. We aimed to estimate the burden of scrub typhus in India.MethodologyWe performed a systematic review of published literature on scrub typhus from India to extract information on epidemiology, morbidity, and mortality. Important databases were searched using keywords and appropriate combinations. We identified observational, interventional, and population-based studies and extracted the data to evaluate the number of cases diagnosed using serology or PCR and the number of deaths due to scrub typhus. We conducted a systematic narrative synthesis to summarize included studies.Principal findingsIn the last decade, there were 18,781 confirmed scrub typhus cases reported in 138 hospital-based studies and two community-based studies. IgM ELISA was used in 122 studies to confirm the cases in majority (89%). The proportion of scrub typhus among acute undifferentiated febrile illness (AUFI) studies was 25.3%, and community seroprevalence was 34.2%. Ninety studies had data published on multiple organ involvement out of which 17.4% of cases had multiple organ dysfunction syndromes, 20.4% patients required ICU admission, and 19.1% needed ventilation. The overall case-fatality rate was 6.3%, and the mortality among those with multi-organ dysfunction syndrome was as high as 38.9%.Conclusion/significanceScrub typhus, a common acute febrile illness in India causing severe morbidity, accounts for a large number of deaths. The burden of the disease has been underappreciated. Early diagnosis and prompt treatment can significantly reduce complications and mortality. Establishing good surveillance and instituting appropriate control measures are urgently needed.

A case of availability bias for COVID-19 causing scrub typhus diagnostic errors.

Although patients with scrub typhus develop a maculopapular rash all over the body, patients with COVID-19may also show a similar rash. At the first visit, we did not fully inspect his trunk and extremities under his clothes. Although scrub typhus and COVID-19have some similar symptoms, an eschar is a characteristic symptom of the former, and careful inspection is important to distinguish between the diseases.

Dėmėtosios šiltinės epidemija Lietuvoje Antrojo pasaulinio karo metais (1941–1944 m.)

ANNOTATION. The article dwells on cases of typhus in Lithuania in 1941–1944, offers an analysis of the spread of the disease, the number of cases, and the preventive measures applied by German and Lithuanian officials. It was established that during the German occupation, typhus spread in Lithuania in two ways. The disease was first spread by Soviet prisoners of war, and later by civilians who were evacuated from the Soviet Union. The largest number of cases was recorded in parts of Lithuania where typhus was most often detected before the Second World War. KEYWORDS: typhus, epidemic, prisoners of war, evacuated civilians, sanitation, prevention.

Analysis and simulation of mathematical model for typhus disease in Makassar

The aims of the research is to build a mathematical model for typhus; Analyse and determine the basic reproduction number of the model; model simulations to predict the number of Typhus cases in Makassar City. This stage of the study examines the mathematical model of Typhus transmission by including food and flies as variables, which are the Susceptible-Exposed-Infected-Recovered (SEIR) model; analysed the SEIR model using the matrix generation method, then the model simulation using Maple with secondary data on the number of Typhus cases in Makassar City obtained from the Makassar Health Office. The results obtained are the SEIR model for typhus transmission by including flies and food as a variable which is an eight dimension non-linear differential equation model. This study also provides the analysis results of the SEIR model that Makassar is not worried an area Makassar for Typhus disease, this means the disease Typhus still exists in Makassar, while the calculation results of the basic reproduction number is .R0=0.137≤1, it can be concluded that the spread of typhus in Makassar is at an alarming stage, because a person suffering from typhus does not cause another person to suffer from Typhus. Model simulation results can predict the number of cases of Typhus so that early prevention can be done immediately and become the government’s attention to prevent the spread of typhus in Makassar City

English

BACKGROUND Scrub typhus is a febrile disease, the clinical diagnosis of which is difficult due to its vague symptoms. Scrub typhus is diagnosed mainly via serological tests. Sensitivity of Weil Felix was found to be poor, but the specificity of Weil Felix was variable in different studies. Enzyme linked immunosorbent assay (ELISA) IgM is known to be a sensitive test, but its specificity was variable in different studies. Therefore, in this study we have compared these two tests with the gold standard IFA. METHODS The study was performed as a cross-sectional study. Among the suspected scrub typhus cases, fifty consecutive IFA scrub typhus positive and fifty consecutive IFA negative samples were taken for comparison of Weil Felix and ELISA tests. The indirect fluorescent antibody test (IFA) was taken as the gold standard. RESULTS The sensitivity of ELISA and Weil Felix at a titre of 1 : 160 was found to be 96 % and 40 % respectively. The specificity of ELISA and Weil Felix at 1 : 160 and was found to be 88 % and 94 % respectively. CONCLUSIONS Scrub typhus should be kept in mind as a possible diagnosis in acute febrile illnesses. Weil - Felix was found to have a good specificity but low sensitivity. Hence, if the results by Weil Felix are negative, scrub typhus cannot be ruled out and may require further testing. ELISA showed good sensitivity making it a preferable screening test but is not highly specific and confirmation with IFA may be required when feasible. KEYWORDS Scrub Typhus, ELISA, Weil Felix, IFA, Laboratory Diagnosis

Clinical profile and predictors of severity in paediatric scrub typhus with pulmonary involvement

Pulmonary involvement is common in children with scrub typhus. Our paper outlines the clinical characteristics of pulmonary involvement and analyses the predictors of its severity. All scrub typhus serology-positive (optical density >0.5) children with pulmonary symptoms were included. Of 506 serology-positive scrub typhus cases, 256 (50.5%) had pulmonary symptoms, of whom 50 (9.8%) were severe. These severe cases were compared with non-severe cases. Interstitial pneumonitis was the commonest chest radiographic finding. Logistic regression analysis identified 'fever clearance time' >48 h, facial puffiness, maculopapular rash and anaemia to be significantly associated with severe pulmonary involvement.

Validation of a Clinical Risk-scoring Algorithm for Scrub Typhus Severity in South India.

BackgroundA clinical risk-scoring algorithm (CRSA) to forecast the scrub typhus severity was developed from two general hospitals in Thailand where patients were classified into three groups—nonsevere, severe, and fatal. In this study, an attempt was made to validate the risk-scoring algorithm for prognostication of scrub typhus severity in India.Materials and methodsThis prospective study was conducted at a hospital in South India between November 2017 and March 2019. Patients of scrub typhus were categorized into nonsevere, severe, and fatal according to the CRSA. The patients were also grouped into severe and nonsevere according to the definition of severe scrub typhus which was used as a gold standard. The obtained CRSA score was validated against the classification based on the definition of severe scrub typhus. Receiver operating characteristics (ROC) curve for the scores was plotted and the Youden's index for optimal cutoff was used.ResultsA total of 198 confirmed cases of scrub typhus were included in the study. According to the ROC curve, at a severity score ≥7, an optimal combination of sensitivity of 75.9% and specificity of 77.5% was achieved. It correctly predicted 76.77% (152 of 198) of patients as severe, with an underestimation of 10.61% (21 patients) and an overestimation of 12.63% (25 patients).ConclusionIn the present study setting, a cutoff of ≥7 for severity prediction provides an optimum combination of sensitivity and specificity. These findings need to be validated in further studies.How to cite this articleGulati S, Chunduru K, Madiyal M, Setia MS, Saravu K. Validation of a Clinical Risk-scoring Algorithm for Scrub Typhus Severity in South India. Indian J Crit Care Med 2021;25(5):551–556.

A Clinical Case of Scrub Typhus in the United States Forces Korea Patient with Eschar and Genetic Identification of Orientia tsutsugamushi Using Multiplex PCR-Based Next-Generation Sequencing.

An epidemiological investigation was conducted for a scrub typhus case reported in a U.S. Forces Korea military patient in the Republic of Korea in November 2018. The patient had a fever, maculopapular rash, and an eschar. The full-length sequence of Orientia tsutsugamushi 56-kDa type-specific antigen (TSA) gene was obtained from eschar tissue by multiplex PCR-based Next Generation Sequencing for genetic identification. Based on the 56-kDa TSA gene, the O. tsutsugamushi aligned most closely with the Boryong strain.

Eschar and IgM ELISA in the Diagnosis of Scrub Typhus

AbstractScrub typhus is one of the leading causes of acute febrile illness in India. This study aimed to determine the best diagnostic tool for the identification of scrub typhus and study the possible association between diagnostics and clinical characteristics. Patients with fever of ≤15 days admitted to the hospital satisfying the case definition of 47 kDa quantitative polymerase chain reaction (qPCR) positivity OR scrub typhus IgM ELISA positivity along with the presence of eschar OR Scrub typhus IgM ELISA positivity along with defervescence of fever within 72 h of initiation of specific therapy were recruited. Of the 116 patients satisfying the case definition, 47 kDa qPCR was positive in 43 (37%) patients, whereas IgM ELISA was positive in 104 (90%) patients and eschar was seen in 59 (51%) patients. The median duration of fever was 7.5 days (interquartile range 6–10 days). Multiorgan dysfunction syndrome (MODS) was described in 44 (37.9%) patients. Two patients (1.8%) succumbed to the illness. Presence of eschar and IgM ELISA positivity were detected in 106 (91%) cases. Scrub typhus, even with MODS, has low mortality because of immediate institution of specific therapy due to physician awareness. The presence of eschar and IgM ELISA positivity can be used to detect a majority of cases of scrub typhus.

Clinical profile and complications: scrub typhus in children at a tertiary hospital in south India, Nellore

Background: Rickettsial diseases, including scrub typhus, are emerging across the Asia-Pacific region as a significant source of acute undifferentiated febrile disease. The purpose of the research is to study the clinical profile, symptoms, and results of cases of scrub typhus admitted to rural medical colleges.Methods: From November 2019 to August 2020, this prospective descriptive research was performed at Narayana Medical College, Nellore, Andhra Pradesh, India. Children who were scrub typhus-positive by immunoglobulin M (IgM) enzyme-linked immunosorbent assay (ELISA) were tested.Results: 164 children (more than 40 percent of fever cases) were scrub typhus-positive during the study time. Many of the children had a fever. 84.15 percent, 49.40 percent, 37.20 percent, 56.10 percent, and 25 percent respectively saw high-grade fever, chills, vomiting, cough, and headache. In 63.41 percent of children, Eschar was shown. The typical findings were lymphadenopathy (68.30 percent) and hepatomegaly (more than 57 percent). In 47.56 percent, 25.60 percent, 39.63 percent, and 37.19 percent, shock, respiratory failure, pleural effusion, and ascites were observed. Popular lab results were anemia (70.12 percent) and thrombocytopenia (74.40 percent). Complications were recorded in shock (47.56 percent), ARDS (10.36 percent), meningoencephalitis (7.32 percent), and MODS (1.22 percent). The complications were treated with doxycycline (51.21 percent), azithromycin (12.80 percent), and both drugs (35.97 percent) were used to treat the complications.Conclusions: When a child presents with acute febrile illness, hepatosplenomegaly, lymphadenopathy, anemia with thrombocytopenia, and features suggestive of capillary leak diagnosis of scrub typhus must be considered. Doxycycline or azithromycin, proper fluid boluses, inotropes, and O2 through Jackson-Rees circuit are life-saving for scrub typhus and its complications.

Ectoparasites of some wild rodents /shrews captured from Scrub typhus reported areas in Tamil Nadu, India

ABSTRACT Scrub typhus cases have been reported in Madurai, but very little is known about the distributionpatterns of ectoparasites on rodents and shrews in the Madurai district. To determine the chigger vectors of scrub typhus, Rattus rattus, R. norvegicus, Mus musculus, and Suncus murinus were collected from these areas and the prevalence and mean intensity were calculated as 40% & 14.8 ± 3.9 for chiggers. Mites were collected from burrow soil samples. The chiggers Leptotrombidium deliense and Schoengastiella ligula, both known as vectors for the transmission of Orientia tsutsugamushi in India, were recorded in this study. In addition, Rhipicephalus sanguineus ticks, a putative vector of Indian tick typhus and canine ehrlichiosis, and the oriental rat flea Xenopsylla cheopis, a known vector of the plague pathogen Yersinia pestis, were also reported. They have high zoonotic potential and have been implicated in the transmission of the aforementioned emerging zoonotic diseases. Parapathi is a typical scrub typhus village with lots of rat burrows found around many houses and many reported scrub typhus cases. Rodents and shrews collected from these areas harboured vectors of medical and veterinary importance and act as endemic reservoir for transmitting zoonotic diseases which requires urgent attention for its control. http://www. zoobank.org/urn:lsid:zoobank.org:pub:5EFDD3BC-B9BA-4595-A02E-8AAEB4E7D755

An outbreak investigation of scrub typhus in Nepal: confirmation of local transmission

BackgroundScrub typhus is a largely ignored tropical disease and a leading cause of undifferentiated febrile illness in the areas of tsutsugamushi triangle caused by Orientia tsutsugamushi. It is frequently diagnosed in South Asian countries, although clear epidemiological information is not available from Nepal. After the 2015 earthquake in Nepal, a sudden upsurge in scrub typhus cases was reported. The objective of this study was to investigate epidemiology of scrub typhus and its causative agents in humans, animals, and chigger mites to understand the ongoing transmission ecology.MethodsScrub typhus cases with confirmed diagnosis throughout the country were included in the analysis. Studies were concentrated in the Chitwan district, the site of a major outbreak in 2016. Additional nation-wide data from 2015 to 2017 available from the government database included to analyse the disease distribution by geographical mapping.ResultsFrom 2015 to 2017, 1239 scrub typhus cases were confirmed with the largest outbreak occurring in 2016 with 831 (67.1%) cases. The case fatality rate was 5.7% in 2015 which declined to 1.1% in 2017. A nationwide outbreak of scrub typhus was declared as the cases were detected in 52 out of the 75 districts of Nepal. Seasonal trend was observed with a peak during August and September. In addition to the human cases, the presence of O. tsutsugamushi was also confirmed in animals (rodents) and chigger mites (Leptotrombidium imphalum) from the outbreak areas of southern Nepal.ConclusionThe detection of O. tsutsugamushi in humans, animals, and chigger mites from outbreak locations and wide-spread reports of scrub typhus throughout the country consecutively for 3 years confirms the ongoing transmission of O. tsutsugamushi with a firmly established ecology in Nepal. The country’s health system needs to be strengthened for systematic surveillance, early outbreak detection, and immediate actions including treatment and preventive measures.

Murine Typhus Infection in Pregnancy: Case Series and Literature Review.

Murine typhus is a flea-borne disease of worldwide distribution with a recent reemergence in the United States of America. There are limited data about the presentation, treatment, and outcomes in the pregnant population. We report on two cases of murine typhus during pregnancy and review the literature to compile previously reported cases. A comprehensive search was performed via the PubMed database for published articles between 1990 and 2020. Seven articles met the criteria of symptomatic pregnant murine typhus infection. A total of 37 patients were identified. Patients frequently presented with a prolonged duration of fevers prior to presentation, headache, and elevated hepatic transaminases. The diagnosis was predominantly based on serology. Treatment varied. Overall, the pregnancy outcome was favorable. Murine typhus can mimic other pregnancy-related pathologies. More exclusive and large-scale studies are needed to learn more of murine typhus during pregnancy.

Describing fine spatiotemporal dynamics of rat fleas in an insular ecosystem enlightens abiotic drivers of murine typhus incidence in humans.

Murine typhus is a flea-borne zoonotic disease that has been recently reported on Reunion Island, an oceanic volcanic island located in the Indian Ocean. Five years of survey implemented by the regional public health services have highlighted a strong temporal and spatial structure of the disease in humans, with cases mainly reported during the humid season and restricted to the dry southern and western portions of the island. We explored the environmental component of this zoonosis in an attempt to decipher the drivers of disease transmission. To do so, we used data from a previously published study (599 small mammals and 175 Xenopsylla fleas from 29 sampling sites) in order to model the spatial distribution of rat fleas throughout the island. In addition, we carried out a longitudinal sampling of rats and their ectoparasites over a 12 months period in six study sites (564 rats and 496 Xenopsylla fleas) in order to model the temporal dynamics of flea infestation of rats. Generalized Linear Models and Support Vector Machine classifiers were developed to model the Xenopsylla Genus Flea Index (GFI) from climatic and environmental variables. Results showed that the spatial distribution and the temporal dynamics of fleas, estimated through the GFI variations, are both strongly controlled by abiotic factors: rainfall, temperature and land cover. The models allowed linking flea abundance trends with murine typhus incidence rates. Flea infestation in rats peaked at the end of the dry season, corresponding to hot and dry conditions, before dropping sharply. This peak of maximal flea abundance preceded the annual peak of human murine typhus cases by a few weeks. Altogether, presented data raise novel questions regarding the ecology of rat fleas while developed models contribute to the design of control measures adapted to each micro region of the island with the aim of lowering the incidence of flea-borne diseases.