Epidemiological Patterns and Public Health Implications of Hand, Foot and Mouth Disease in the Asia Pacific Region

Understanding Hand, Foot, and Mouth Disease and Human Enterovirus 71

Background and Virology

Hand, foot, and mouth disease (HFMD) is a common infectious disease predominantly affecting children. It is characterized by fever, sores in the mouth, and a rash with blisters. HFMD is usually a mild disease, but in certain cases, it can lead to more severe illnesses, including neurological and cardiopulmonary complications, particularly when caused by the human enterovirus 71 (HEV-71). Understanding the virology of HEV-71 is crucial to comprehend the disease’s transmission, pathogenesis, and potential treatment strategies.

The Picornaviridae family, which includes HEV-71, is comprised of non-enveloped, single-stranded RNA viruses. The genome of HEV-71 is approximately 7.4 kb in size, with regions encoding structural and non-structural proteins. The structural proteins are involved in the formation of the viral capsid, while non-structural proteins are crucial for viral replication. Genetic recombination, both intra-typic and inter-typic, is a common phenomenon in HEV-71, contributing to its genetic diversity and the emergence of new epidemic strains, particularly in the Asia Pacific region.

Transmission and Pathogenesis

The transmission of HFMD and HEV-71 is believed to occur through fecal-oral routes in developing areas and via respiratory droplets in developed regions. The virus can survive in the environment for prolonged periods and is resistant to many biocides. HEV-71 has several human cellular receptors, which contribute to its systemic nature in severe cases and its tendency to affect the central nervous system. The involvement of the brainstem and other parts of the brain in severe cases can lead to encephalitis, cardiopulmonary failure, and even death.

Protective Immunity and Clinical Disease

The immune response to HEV-71 is complex, involving both cellular and humoral immunity. Neutralizing antibodies play a crucial role in protection against infection. Maternal antibodies, whether transplacental or through breastfeeding, can provide passive immunity to infants. HFMD is typically caused by coxsackievirus A16 (CV-A16) and HEV-71, with the latter more likely to result in severe illness and complications.

Results and Epidemiology

HEV-71 was first identified in California in 1969. Since then, it has been associated with outbreaks of HFMD worldwide, with significant epidemics occurring in the Asia Pacific region. The reasons for this geographic distribution are not fully understood but may include genetic factors of the virus and host, environmental hygiene, and healthcare standards. The disease often presents in a cyclical pattern, with epidemics occurring every few years, likely due to the accumulation of susceptible individuals or the emergence of new viral genotypes.

Treatment, Prevention, and Control

Currently, there is no specific antiviral treatment for HEV-71. Management is primarily supportive, with severe cases requiring intensive care. Intravenous immunoglobulin (IVIG) has been used with some success, and vaccination efforts are underway. Preventive measures include proper hand hygiene, environmental disinfection, and public health monitoring to detect and control outbreaks.

Impact of the Study

This research provides valuable insights into the virology, epidemiology, and clinical management of HFMD and HEV-71. It underscores the need for continued surveillance, the development of effective treatments and vaccines, and the implementation of public health strategies to prevent and control outbreaks. While the study highlights the challenges posed by HEV-71, it also points to the potential for scientific advancements to mitigate the impact of this infectious disease.

Conclusion and Future Prospects

In conclusion, HEV-71 associated HFMD is a significant public health challenge, particularly in the Asia Pacific region. The disease’s mild nature in most cases belies the potential for severe, life-threatening complications. Future research should focus on developing effective vaccines, antiviral treatments, and public health strategies to prevent and control HEV-71 infections. Additionally, understanding the factors that contribute to the emergence and spread of epidemic strains will be crucial in global efforts to combat this disease.

Reference

Wong, S. S. Y., Yip, C. C. Y., Lau, S. K. P., & Yuen, K. Y. (2010). Human enterovirus 71 and hand, foot and mouth disease. Epidemiology and Infection, 138(8), 1071–1089. http://dx.doi.org/10.1017/S0950268809991555