Severe interstitial pneumonia due to murine typhus in a patient returning from Bali

Flea-Borne Typhus as a COVID-19 Mimic: A Report of Four Cases

Flea-borne typhus (FBT), due to Rickettsia typhi and R. felis, is an infection causing fever, headache, rash, hepatitis, thrombocytopenia, and diverse organ manifestations. Cough occurs in about 30% of patients with FBT, and chest X-ray abnormalities are seen in 17%. Severe pulmonary manifestations have also been reported in FBT, including adult respiratory distress syndrome and pulmonary embolism. Because of these pulmonary manifestations, FBT can mimic Coronavirus Illness 2019 (COVID-19), a febrile illness with prominent respiratory involvement. Flea-borne typhus and COVID-19 may also have similar laboratory abnormalities, including elevated ferritin, C-reactive protein, and D-dimer. However, elevated transaminase levels, rash, and thrombocytopenia are more common in FBT. Herein, we present four cases of patients with FBT who were initially suspected to have COVID-19. These cases illustrate the problem of availability bias, in which the clinician thinks a particular common condition (COVID-19 in this case) is more prevalent than it actually is.

Climate factors driven typhus group rickettsiosis incidence dynamics in Xishuangbanna Dai autonomous prefecture of Yunnan province in China, 2005-2017

BACKGROUND

Typhus group rickettsiosis (TGR), which is a neglected vector-borne infectious disease, including epidemic typhus and endemic typhus. We explored the lag effects and nonlinear association between meteorological factors and TGR incidence in Xishuangbanna Dai autonomous prefecture from 2005 to 2017, China.

METHODS

A Poisson regression with a distributed lag nonlinear model (DLNM) was utilized to analyze TGR cases data and the contemporaneous meteorological data.

RESULTS

A J-shaped nonlinear association between weekly mean temperature and TGR incidence was found. The cumulative exposure to weekly mean temperature indicated that the RR increased with the increment of temperature. Taking the median value as the reference, lower temperatures could decrease the risk of TGR incidence, while higher temperatures could increase the risk of TGR incidence and last for 21 weeks. We also found a reversed U-shaped nonlinear association between weekly mean precipitation and TGR incidence. Precipitation between 5 mm and 13 mm could increase the risk of TGR incidence. Taking the median value as the reference, no precipitation and lower precipitation could decrease the risk of TGR incidence, while higher precipitation could increase the risk of TGR incidence and last for 18 weeks.

CONCLUSIONS

The prevention and control measures of TGR should be implemented according to climatic conditions by the local government and health departments in order to improve the efficiency.

Rickettsia typhi infection presenting as severe ARDS

Murine typhus, also known as endemic typhus, is a disease resulting from an infection caused by the gram-negative bacillus Rickettsia typhi. Murine typhus is identified worldwide, predominantly in tropical and subtropical geographic locations. Transmission occurs through direct inoculation by an arthropod vector, most commonly the rat flea, Xenopsylla cheopis. rickettsial infections are notorious for disseminated infections throughout the endothelial cells. The increase in permeability is an immediate consequence and has the potential of leading to non-cardiogenic pulmonary edema, otherwise known as acute respiratory distress syndrome (ARDS). Clinical manifestations are non-specific and initially mimic typical viral etiologies, obscuring early diagnosis. As a result, clinicians often do not include rickettsial infections in their differential diagnoses. Definitive diagnosis is based on clinical recognition, epidemiologic awareness, and serological testing. Here we present a confirmed case of murine typhus in a young non-immunocompromised patient who developed ARDS one week from the initial onset of symptoms.

Diagnosis of Murine Typhus by Serology in Peninsular Malaysia: A Case Report Where Rickettsial Illnesses, Leptospirosis and Dengue Co-Circulate

Murine typhus is a rarely diagnosed cause of acute febrile illness in Malaysia, and its true disease burden is unknown. We report a case of an acute murine typhus infection in a patient living in a small city in Peninsular Malaysia, presenting with fever, rash, and headache. Unresponsive to the initial empirical treatment for leptospirosis, he showed a rapid response to doxycycline when murine typhus was diagnosed later. This case highlights the importance of considering murine typhus as a diagnostic in cases of acute febrile illness in urban and sub-urban areas, such as that of in Peninsular Malaysia.

ConcomitantPlasmodium vivaxmalaria and murine typhus infection with pulmonary involvement

We report a case of Plasmodium vivax and murine typhus coinfection in a 30-year-old woman who presented with intermittent, high-grade fever. Her peripheral blood smear showed ring-form trophozoites of P. vivax, with an initial murine typhus serological test being negative. Although the P. vivax infection was successfully treated, she still had intermittent, high-grade fever, developed dyspnoea and bilateral interstitial pneumonitis shown in the chest X-ray. Thus, coinfection was suspected, and empirical antibiotics were given. The second serological test confirmed the concomitant murine typhus infection, and antibiotics treatment were successful with the complete recovery. This case emphasises that an initial negative murine typhus serological test does not necessarily rule out the presence of the disease. A follow-up murine typhus serological or molecular test within 1–2 weeks is therefore recommended.