The Centers for Disease Control has lifted its recommendation to avoid travel to Mexico, because the outbreak in Mexico appears to be slowing in many areas and because the risk of severe disease from H1N1 virus infection now appears to be less than originally thought. The CDC advises that those at high risk for influenza complications should speak with their physicians about the risks of traveling to Mexico and might consider postponing their trips. The high risk groups include pregnant women, those under age 5 or over age 65, those with compromised immune systems, and those with significant underlying medical problems.

In view of the ongoing swine flu outbreak, the Centers for Disease Control has advised against all non-essential travel to Mexico until further notice. Those who travel to Mexico should consider taking Tamiflu 75 mg daily to prevent infection.

An outbreak of a flu-like illness caused by a previously unknown swine flu virus has been reported from Mexico, causing more than 800 cases and more than 60 deaths so far. Most of the cases have occurred in Mexico City. Smaller outbreaks have been reported from San Luis Potosi in central Mexico and from Mexicali, near the border with the United States. All schools, museums, and libraries in Mexico City have been closed. Also, 20 cases have been reported from the United States (New York City, California, Texas, Kansas and Ohio) and four cases from Nova Scotia, Canada. No travel precautions are recommended at this time, but any traveler to Mexico who develops flu-like symptoms should immediately seek medical attention.

An increase in the number of cases of pertussis (whooping cough) has reported from several states, including New South Wales, Queensland, and Victoria. Pertussis is a highly contagious respiratory infection, spread by exposure to an infected person who is coughing or sneezing. All travelers to Australia should be fully immunized against pertussis. The vaccine is generally given in combination with the vaccines for tetanus and diphtheria.

More than 30 cases of yellow fever have been reported from the states of Rio Grande do Sul and Sao Paulo since October 2008. A single case has also been reported from Minas Gerais. Yellow fever vaccine is strongly recommended for all travelers to these states. Travelers should also protect themselves from mosquito bites by applying insect repellent and keeping themselves covered.

An outbreak of Chagas disease has been reported from Chichiriviche de la Costa, in the western part of the state of Vargas. The outbreak appeared to have been caused by contaminated guava juice. Travelers to Venezuela and other countries in South America should avoid consuming homemade juice or wine, especially from roadside stands.

A small number of human cases of avian influenza (bird flu) continue to be reported, mostly from Egypt, Indonesia, and Viet Nam. Almost all human cases have occurred in those who have had direct contact with infected poultry. As before, travelers should not hesitate to visit countries affected by avian influenza, but should avoid exposure to live poultry, including visits to poultry farms and open markets with live birds; should not touch any surfaces that might be contaminated with feces from poultry or other animals; and should make sure all poultry and egg products are thoroughly cooked.

An outbreak of hand, foot, and mouth disease has been reported from China, chiefly affecting young children. The northeastern provinces of Henan and Shandong have been especially affected. Hand, foot, and mouth disease is characterized by fever, oral blisters, and a rash or blisters on the palms and soles, usually occurring in young children. Most cases resolve uneventfully, but a small percentage are complicated by encephalitis (inflammation of the brain), myocarditis (inflammation of the heart muscle), or pulmonary edema (fluid in the lungs). The disease is caused by enteroviruses, which are transmitted by exposure to fecal material from infected individuals. There is no vaccine. The key to prevention is good personal hygiene and scrupulous hand-washing, especially after defecation and before handling food. No travel restrictions are recommended.

An alert for Murray Valley encephalitis has been issued for the Kimberley and the Pilbara in Western Australia after blood tests showed the disease was found in sentinel chickens. The increase in viral activity occurred after weeks of flooding. Murray Valley encephalitis is transmitted by "common banded" mosquitoes, which breed in grassy and reed swamps and pools and bite after sundown. Murray Valley encephalitis may cause fever, headaches, neck stiffness, confusion, seizures, nausea, vomiting, tremors, and dizziness. Severe cases may progress to coma and death. There is no vaccine. Travelers to Western Australia should protect themselves from mosquito bites by applying repellent and keeping themselves covered.

An outbreak of dengue fever has been reported from northern Argentina, especially affecting the province of Chaco. Dengue fever is a mosquito-borne viral infection which is sometimes complicated by hemorrhage or shock. There is no vaccine. Travelers to northern Argentina should protect themselves from mosquito bites by applying repellent and keeping themselves covered.

A major outbreak of dengue fever has been reported from Bolivia, chiefly affecting the department of Santa Cruz. Cases have also occurred in Beni, Pando, Cochabamba, Chuquisaca and La Paz. Dengue fever is a mosquito-borne viral infection which is sometimes complicated by hemorrhage or shock. There is no vaccine. Travelers to Bolivia should protect themselves from mosquito bites by applying repellent and keeping themselves covered.

Although no human cases of yellow fever have been reported from Trinidad since 1979, recent yellow fever cases in monkeys indicate that the virus is continuing to circulate in forested areas of the island. Yellow fever vaccine is recommended for travelers who will be going to Trinidad, except for cruise ship passengers who do not disembark from the ship or travelers visiting only Port of Spain, who may consider foregoing vaccination. Yellow fever vaccine is not recommended for those visiting only Tobago.

An outbreak of meningococcal meningitis has been reported from the states of Meghalaya, Tripura and Mizoram in northeastern India. Meningococcal infections are spread person-to-person by exposure to secretions from the nose or throat, and may lead to meningitis, marked by the abrupt onset of fever, headache, stiff neck, and lethargy, frequently with a rash. Meningococcal vaccine is recommended for all travelers to Meghalaya, Tripura and Mizoram.

A series of mumps outbreaks have been reported from the United Kingdom, chiefly affecting schoolchildren and university students. Mumps is a viral infection which is spread by direct contact with or inhalation of oral or nasal secretions from an infected person. All travelers born after 1956 should make sure they have had either two documented MMR immunizations or a blood test showing mumps immunity. This does not apply to people born before 1957, who are presumed to be immune.

A measles outbreak has been reported from the canton of Vaud. Measles outbreaks occur regularly in Switzerland, due to low vaccination rates among Swiss2/8/2009 children. All travelers born after 1956 should make sure they have had either two documented MMR or measles immunizations or a blood test showing measles immunity. Those born before 1957 are presumed to be immune. Although measles immunization is usually begun at age 12 months, children between the ages of 6 and 11 months should be given an initial dose of measles or MMR vaccine before traveling to Switzerland.

An outbreak of leptospirosis has been reported from Fiji after massive flooding caused by torrential rains. Leptospirosis is transmitted to humans by exposure to water contaminated by the urine of infected animals. Symptoms may include fever, chills, headache, muscle aches, conjunctivitis (pink eye), light sensitivity, and rash. Most cases resolve uneventfully, but a small number may be complicated by meningitis, kidney failure, liver failure, or hemorrhage. There is no vaccine. Travelers exposed to potentially infected water can lower their risk of becoming ill by taking 200 mg of doxycycline.

A case of Marburg hemorrhagic fever has been reported in a U.S. citizen who had visited “the python cave” in the Maramagambo Forest in western Uganda (at the southern edge of Queen Elizabeth National Park). This cave contains large numbers of fruit bats, which can harbor Marburg virus. In July 2008, a fatal case of Marburg hemorrhagic fever occurred in a Dutch tourist who had visited the same cave. Travelers should avoid these caves until further notice

A rabies outbreak related to infected dogs has been reported from the southern tip of Bali. Travelers to Bali should avoid touching all animals, including pet dogs and cats and wild animals such as monkeys. Rabies vaccine is recommended for travelers spending a lot of time outdoors, for travelers at high risk for animal bites, such as veterinarians and animal handlers, for long-term travelers and expatriates, and for travelers involved in any activities that might bring them into direct contact with bats. Children are considered at higher risk because they tend to play with animals, may receive more severe bites, or may not report bites.

An outbreak of dengue fever has been reported from the northern suburbs of Cairns. Dengue fever is a mosquito-borne viral infection which is sometimes complicated by hemorrhage or shock. There is no vaccine. Travelers to northern Queensland should protect themselves from mosquito bites by applying repellent and keeping themselves covered.

A nationwide cholera outbreak caused by contaminated drinking water has been reported from Zimbabwe, causing tens of thousands of cases. The main symptoms of cholera are profuse watery diarrhea and vomiting, which in severe cases may lead to dehydration and death. Most travelers are at low risk for infection, as long as they drink and use only bottled water. Cholera vaccine, which is available in many countries but not the United States, is recommended only for certain high-risk individuals, such as relief workers, health professionals, and those traveling to remote areas where cholera epidemics are occurring and there is limited access to medical care.

An outbreak of dengue fever has been reported from St. Maarten, causing hundreds of cases. Dengue fever is a mosquito-borne viral infection which is sometimes complicated by hemorrhage or shock. There is no vaccine. Travelers to St. Maarten should protect themselves from mosquito bites by applying repellent and keeping themselves covered.