Outbreak of Chikungunya Fever: North-East Italy

Update: September 28, 2007

The Public Health Agency of Canada (PHAC) is monitoring an outbreak of chikungunya fever in the province of Ravenna, located in the region of Emilia-Romagna, in North-East Italy. Chikungunya fever is a mosquito-borne disease and travellers to Ravenna are advised to use personal precautions to reduce their exposure to mosquito bites - see: Recommendations below.

Between July 4th and September 14th, 2007 a total of 101 confirmed cases, with a further 133 suspected cases of chikungunya fever were reported in the province of Ravenna. While the majority of cases were reported in the villages of Castiglione di Ravenna and Castiglione di Cervia, sporadic cases within the region have also been reported.  Although imported cases of chikungunya fever have been reported in Europe in the past, this outbreak represents the first documented instance of indigenous (local) transmission.  

Laboratory testing has confirmed that local “tiger mosquitoes” (Aedes albopictus) are responsible for transmitting the virus in this outbreak. A team of public health experts led by the European Centre for Disease Prevention and Control (ECDC) gathered in Ravenna last week to examine the implications of the chikungunya outbreak. The team concluded that local transmission could be experienced in other European countries where the tiger mosquito is present. Increased surveillance by those countries is recommended to ensure the rapid identification of newly infected persons, as well as the timely implementation of appropriate control measures.

Source: European Centre for Disease Prevention and Control (ECDC), World Health Organization (WHO)

Chikungunya virus is most commonly transmitted to humans through the bite of an infected mosquito; specifically Aedes aegypti and Aedes albopictus, which typically bite during daylight hours, with peak periods of biting activity during the morning for several hours after sunrise and in the late afternoon for several hours before sunset.

Symptoms of infection, which generally last three to seven days, include the sudden onset of fever, headache, severe joint pain and rash. Although rare, the infection can result in meningoencephalitis (swelling of the brain), especially in newborns and those with pre-existing medical conditions.  Pregnant women can pass the virus to their fetus.  Residual arthritis, with morning stiffness, swelling, and pain on movement, may persist for weeks or months after the initial illness.  Severe cases of chikungunya can occur in the elderly, in the very young (newborns), and in those who are immunocompromised, and may rarely result in death.  Canadians travelling to areas where chikungunya is endemic have contracted the disease. Large outbreaks of chikungunya fever have recently occurred in sub-Saharan Africa, India, South-East Asian and the Philippines, where the virus is endemic.

There is no vaccine that protects against chikungunya virus.  Treatment for chikungunya typically involves treating the symptoms and includes bed-rest and the use of non-aspirin analgesics during the phase of illness where the symptoms are most severe.  Using protective measures to prevent being bitten by an infected mosquito remains the only means to reduce the risk of exposure.

Recommendations

The Public Health Agency of Canada strongly recommends that travellers to the province of Ravenna take the following personal precautions to reduce their risk of exposure to mosquitoes:

• apply a DEET-based insect repellent to exposed skin;
• when possible, remain in well-screened or completely enclosed, air-conditioned areas during peak biting times; and
• wear light-coloured clothing with full-length pant legs and sleeves;

The Public Health Agency of Canada's Committee to Advise on Tropical Medicine and Travel (CATMAT) produces evidence based statements and guidelines.  For additional information on insect and other arthropod bite prevention visit CATMAT's Statement on Personal Protective Measures to Prevent Arthropod Bites

As a reminder...

The Public Health Agency of Canada routinely recommends that Canadian international travellers consult their personal physician or a travel clinic six to eight weeks prior to international travel, regardless of destination, for an individual risk assessment to determine their individual health risks and their need for vaccination, preventative medication, and personal protective measures.

Additional information:

Chikungunya Information Sheet from the World Health Organization Regional Office for South-East Asia:  http://www.searo.who.int/en/section10/section2246.htm