'Tomato flu' a new epidemic in India: Virology, epidemiology, and clinical features

Abstract

This article aims to highlight the current update on the 'tomato flu' outbreak in India. Recently there was an outbreak of a new illness in some parts of India. The disease was very contagious and it manifested with a rash mainly noticed in children younger than nine years. The rash was very painful and blisters were the size of small tomatoes, hence it was termed 'tomato flu'. A detailed literature review was performed on the virology, replication, epidemiology, and clinical features of this disease. The current outbreak was compared with similar other diseases of the past. The affected children exhibited severe rash in the palms, soles, oral cavity, and other body parts. They developed febrile illness with a sore throat, and myalgia followed by blisters on the tongue, gums, and cheeks. The affected children did not develop any complications leading to death. The therapy involved mainly symptomatic, supportive treatment with isolation and maintaining hygienic practices. The causative agent was identified to be Coxsackievirus A16, an RNA virus belonging to the family, Picornaviridae. We conclude that the recent Indian epidemic of this disease might be due to a new variant of Coxsackievirus A16 actually causing HFMD.

Keywords: Blisters; CA-16, Coxsackievirus A16; CA-16, HFMD; Clinical features; Coxsackievirus A16; HFMD, hand foot and mouth disease; Hand foot and mouth disease; Rash; ‘Tomato flu’.

Fig. 1

Vesiculobullous blister in a patient with ‘tomato flu’ (image credit: istockphoto. com/apomares).

Fig. 2

Electron micrograph of ‘tomato flu’ agent, the Coxsackievirus (image credit: CDC/Dr. Erskine Palmer).

Fig. 3

A schematic diagram of the viral replication process The virus is taken up into the cell when the receptor binds to the canyon of the virus (1). The viral RNA is released into the cytoplasm (2), this serves as a template for translation which produces the polyprotein (3). The polyprotein undergoes proteolytic processing to release structural and non-structural viral proteins which are further processed to result in capsid proteins and replication proteins respectively (4). The viral replication proteins mediate the replication of the viral RNA (5). This produces a negative stranded intermediate that is used as a template for synthesis of positive stranded RNA molecules which can also undergo another round of translation (6). The capsid proteins form the capsid of the virus (7a) into which the positive stranded RNA are packaged into (7b) forming the infectious viral particles. These new virus particles are released upon cell lysis (8).

Fig. 4

Macules, papules and vesicles around the mouth of a child due to HFMD (image credit: Daily Mail UK).

Fig. 5

Maculopapular rash on the palm of HFMD patient (image credit: reddit. com/user/sleekpaprika69).

Fig. 6

A summarised diagram on the disease process and management.