Chikungunya, second autochthonous case in Veneto: what is the 'writhing' disease

Chikungunya is not transmitted from person to person, but only through the bite of infected Aedes mosquitoes. Until now, all confirmed cases of chikungunya in Veneto were related to travel to endemic areas. The identification of an autochthonous case therefore represents a significant event, probably linked to the intensification of international travel in the summer, with people returning from countries where the disease is present, and to climatic conditions favourable to the proliferation of the tiger mosquito.

The first known outbreak was described in 1952 in Tanzania, although an epidemic had already been described in Indonesia in 1779, possibly attributable to the same viral agent. Currently, the infection has been identified in over 60 countries in Asia, Africa, Europe and the Americas. In Italy, outbreaks of local transmission of chikungunya occurred in 2007 and 2017.

Symptoms and clinical picture

After a variable incubation period of up to 12 days (3-7 days on average), fever and joint pains suddenly appear that limit the patients' movements (hence the name chikungunya, which in Swahili means 'that which bends' or 'twists'), who then tend to remain absolutely motionless and assume antalgic positions. Other symptoms include muscle pain, headaches, fatigue and skin rash. Joint pain is often debilitating, generally lasting a few days but can also be prolonged.

In most cases, patients recover completely, however, in some cases joint pain may persist for months or even years. Often the symptoms in infected persons are mild and the infection may go unrecognised or misinterpreted, especially in areas where dengue is present. Ocular, neurological, cardiac and gastrointestinal complications have occasionally been reported. Serious complications rarely occur, however in the elderly the disease can be a contributory cause of death.

The chikungunya virus infection is transmitted through the bite of a female mosquito of the Aedes genus, such as Aedes aegypti and Aedes albopictus (the tiger mosquito). The virus responsible belongs to the togaviridae family, of the alphavirus genus.

Diagnostic confirmation is carried out by detecting the virus or specific antibodies in blood samples as stated in the National Plan for Arbovirosis (Pna). The Pna guides strategies and procedures for the diagnosis and management of mosquito-borne diseases, including chikungunya. The Department of Infectious Diseases of the Istituto Superiore di Sanità (Iss) houses the national reference laboratory for arboviruses.

There are no specific antiviral treatments and treatment focuses primarily on alleviating symptoms. Currently, no vaccines against chikungunya virus infection are licensed in Europe. Recently, a vaccine was approved in the US.

Prevention of the disease consists first and foremost in preventing or minimising mosquito bites. It is useful to follow the following general precautions: - attach mosquito nets to windows and turn on air conditioning at least in rooms where people stay; - wear light-coloured clothes that do not leave parts of the body uncovered (long-sleeved shirts, long trousers, etc.), as dark colours attract mosquitoes; - apply repellents to uncovered parts of the body, bearing in mind that sweat reduces their effect. Pregnant women and children should consult their doctor or pharmacist before using these products, while particular attention should be paid to children under the age of three months, for whom use is not recommended. Moreover, it is essential to bear in mind that some mosquitoes, which are the vectors responsible for transmitting this disease, are active during the day. Especially on hot summer days, they occur with greater intensity in the morning hours and late afternoon, until sunset.

To reduce the risk of epidemics transmitted by mosquitoes of the Aedes genus, the most effective means is the systematic and continuous control of the mosquito that acts as a vector for the disease. Since it can reproduce effectively in man-made areas thanks to even minimal water stagnation, it is necessary to systematically eliminate all water stagnation (e.g. in saucers, open containers in gardens) during the vector's periods of activity and to facilitate periodic disinfestation campaigns aimed at reducing the Aedes population.

The Higher Institute of Health has released updated data on the infections of dengue arboviruses, chikungunya, zika, tick-borne meningoencephalitis (TBE) and Toscana virus. From 1 January to 5 August 2025 (weekly update) there were 111 confirmed dengue cases in the national surveillance system, of which 107 cases were associated with foreign travel and 4 indigenous cases, with a median age of 41 years and 58% of infected persons being male and no deaths. Two different local transmission events of the dengue virus were identified in two different regions. Further epidemiological investigations are ongoing. From 1 January to 29 July 2025 (monthly update), the national surveillance system had 32 confirmed cases of chikungunya, 30 of which were associated with foreign travel and 2 indigenous cases, with a median age of 46.5 years, 53% of male infected and no deaths. During the same time period, 4 cases of zika virus were recorded, all imported; 23 cases of TBE (all autochthonous, median age 52 years, 57% male, no deaths) and 38 cases of Toscana virus (all autochthonous, median age 59.5 years, 74% male, no deaths).