Human H1N1 virus can spread from human- to-human and through coughing and sneezing. Symptoms include fever, cough, sore throat, runny nose, muscle pain and headache and in some, diarrhea. As vaccines for human seasonal flu do not provide protection against H1N1 viruses and H1N1 may cause death, you are advised to seek medical consultation from public clinics or the hospital if your fever is contagious.

Avian Flu (H5N1) is a strain of influenza previously known to infect birds only, but human cases were documented in Hong Kong in 1997 and 2003. It is likely to result in high fever, chest infection, respiratory distress, multiple organ failure and in some cases, death. The virus is believed to be transmitted from infected live birds to humans. The best protection is to stay away from live poultry.

This viral disease transmitted by the Aedes mosquito is found in many Southeast Asian countries. The fever is mild and victims recover within several days. However, multiple infections by different strains of the virus can lead to a more severe infection that can be fatal. The best protection against dengue fever is to prevent the spread of mosquitoes and their bites.

Cholera is caused by a group of bacteria commonly found in unclean water. Transmission of the disease occurs mainly through contaminated food, especially seafood. The infection is more prevalent during the summer months. Ensure that all food is cooked thoroughly before consumption, and only drink boiled or bottled water.

The "flu season" in Hong Kong usually occurs from January to March and from July to August. Most people recover completely in 1 to 2 weeks. The influenza vaccination can help reduce medical complications and deaths especially amongst the elderly and patients with chronic cardiac or respiratory diseases. Vaccinations should be applied yearly due to the emergence of new viral strains. Please consult your physician if you require this.

In 2003, an outbreak of Atypical Pneumonia, also known as Severe Acute Respiratory Syndrome affected the world including Hong Kong. SARS mainly spread through close person-to-person contact, especially via respiratory droplets produced by coughs or sneezes.

Middle East Respiratory Syndrome Coronavirus, formerly known as novel coronavirus, has only recently been identified in humans, and is different from other coronaviruses (including SARS-coronavirus). Infected persons may present with acute serious respiratory illness with symptoms including fever, cough, shortness of breath and breathing difficulties. Most patients develop pneumonia. Many also have gastrointestinal symptoms or kidney failure. In people with immune deficiencies, the disease may have atypical presentation, such as diarrhea. The incubation period can be up to 14 days. The mode of transmission is still uncertain at the moment, although recent studies support that camels serve as the primary source of the disease.