Rickettsial Diseases of Recent Significance in India

Abstract

Rickettsial diseases are considered as re-emerging zoonotic diseases in India caused by rickettsial pathogens. The rickettsial organisms are obligate intracellular vector-borne pathogens causing wide-ranging symptoms. Rickettsia is subdivided into typhus and spotted fever groups. The reports of the disease have been increasing since the start of the 20th century in different parts of India mainly in rural areas with abundant vector populations especially in the post-monsoon season (August-November). The reports of outbreaks are recorded in various states such as Tamil Nadu, Himachal Pradesh, Manipur, Delhi, Puducherry, Uttarakhand, Jammu and Kashmir, Maharashtra, Karnataka, West Bengal and northestern parts of India. The outbreak of Scrub typhus is found to be the major among the diseases. However, the burden of the disease in India remains still unclear owing to the lack of accurate diagnostic facilities. The larval stages of the vectors are vital to the transmission of the disease and cause symptoms such as eschar formation present in 50%–80% of cases, fever, vomiting, headache, abdominal pain, breathlessness and lymphadenopathy. With the advancement in molecular biology, PCR and qPCR and serological assays such as Weil-felix and ELISA are adopted for diagnostic purposes. Surveillance strategies, avoidance of open defecation and urination, and wearing fully covered clothes are key strategies to prevent infection.