West Nile fever is a zoonosis caused by a virus of the Flaviviridae family and is widespread in Africa, Western Asia, Europe, Australia, and America. The reservoirs of the virus are wild birds, while mosquitoes, mainly belonging to the Culex genus, which includes the common mosquito, act as vectors. WNv remains primarily confined to a wild bird-mosquito cycle, but under certain favorable circumstances, it can also be transmitted to humans through the bite of these insects. Organ transplants and blood transfusions constitute means of transmission, although they are very rare. West Nile fever is not transmitted from person to person through contact with infected people. The virus also infects other mammals, especially horses, but in some cases also dogs and cats. The incubation period varies between 2 and 14 days, but most infected people show no symptoms. Only 20% present mild symptoms: fever, headache, nausea, vomiting, enlarged lymph nodes, skin rashes, while in 1% of cases, symptoms are more severe. Some neurological effects can be permanent. In the most severe cases (about 1 in a thousand), the virus can cause lethal encephalitis. The circulation of the West Nile virus (WNv) has been detected in 14 Italian Regions: Basilicata, Calabria, Emilia-Romagna, Friuli Venezia Giulia, Lazio, Liguria, Lombardy, Molise, Piedmont, Puglia, Sardinia, Sicily, Tuscany, Veneto.
Prevention
There is no vaccine available for humans against West Nile fever, so prevention consists mainly of avoiding mosquito bites and preventing them from breeding easily. The use of skin repellents, wearing long pants and long-sleeved shirts when outdoors, and staying in environments protected by mosquito nets and/or equipped with household insecticide diffusers help reduce the risk of contracting the disease. It is also important to reduce larval breeding sites by frequently emptying containers with stagnant water and treating permanent stagnant water (e.g., manholes) with appropriate larvicide.Lyme borreliosis is an infection caused by a spirochete of the genus Borrelia, which predominantly affects the skin, joints, nervous system, and internal organs. It can manifest with severe symptoms and, if not properly treated, can take a chronic course. It is the most widespread vector-borne pathology in North America and Europe. In Trentino, cases of infection are reported every year. The main vector of Lyme borreliosis is represented by the wood tick (Ixodes ricinus), while the main reservoirs are represented by wild animals (rodents, roe deer, deer, foxes, hares). The tick can acquire the pathogen from an infected animal during the blood meal necessary to moult to the next stage of development, remaining infected for its entire life cycle. The disease generally starts with a red spot on the skin that expands slowly, typically taking a target shape. After a few weeks (but in some cases even months), neurological disorders can develop characterized by migratory arthralgia, myalgia, meningitis, polyneuritis, myocarditis, and atrioventricular conduction disorders. Months or years after the infection, there may be changes to the musculoskeletal system (chronic arthritis), the central and peripheral nervous system, the skin, and the cardiovascular system.
Prevention
Prevention consists mainly of avoiding tick bites, avoiding walking at the edges of paths with tall grass, wearing long clothes, and placing socks over pants. It is very important at the end of the excursion to check clothes and the entire skin surface for any ticks, which must be removed immediately. Extraction must be done using fine-tipped tweezers, grasping the tick at the base and pulling upwards. There are currently no vaccines registered in Italy. Furthermore, the disease does not lead to the development of immunity, so the infection can be contracted multiple times during life.Tick-borne encephalitis (TBE) is a zoonosis caused by a virus belonging to the Flavivirus genus and is a disease of the central nervous system. TBE is present in endemic foci in many countries of Central, Eastern, and Northern Europe, including Italy. Cases of TBE have also been diagnosed in Trentino in recent years. Wild rodents constitute the main reservoir of this virus, while the vector is represented by the tick, and particularly Ixodes ricinus (the wood tick), which also acts as a reservoir. Several animals, wild or domestic such as ungulates, sheep, and goats, contribute to the maintenance of the infection's transmission cycle. The tick can acquire the virus from an infected animal during the blood meal necessary to molt to the next stage of development, remaining infected for its entire life cycle. In humans, in about 70% of cases, an asymptomatic infection or one with mild symptoms occurs, which may go unnoticed. In the remaining 30% of cases, 3-28 days after the tick bite, there is a first phase with flu-like symptoms and generally no further consequences. In 10-20 percent of these cases, after a symptom-free interval of 8-20 days, a second phase begins characterized by central nervous system disorders (encephalitis, flaccid paralysis with a fatal outcome in 1% of cases). In children and younger individuals, TBE generally shows a milder course, with a progressive increase in severity as age progresses.
Prevention
Prevention consists mainly of avoiding tick bites, avoiding walking at the edges of paths with tall grass, wearing long clothes, and placing socks over pants. It is very important at the end of the excursion to check clothes and the entire skin surface for any ticks, which must be removed immediately. Extraction must be done using fine-tipped tweezers, grasping the tick at the base and pulling upwards.Prophylaxis
There are no specific cures, but to prevent the onset of the disease, a vaccine is available (for free for the residents of Provincia Autonoma di Trento since 01/01/2018), that involves the administration of three doses (the second at 1-3 months, the third at 9-12 months), with boosters at three-year and subsequently at five-year intervals.Chikungunya is a viral disease caused by a virus belonging to the Alphavirus genus. It is transmitted to humans by the bite of mosquitoes that have, in turn, bitten an infected person. This pathogen is of tropical origin, so it is usually absent in our country. However, it can be accidentally introduced by travellers who go to countries where this disease is endemic for tourism or work and give rise to autochthonous cases thanks to the presence on Italian territory of a competent vector such as the tiger mosquito. Several cases of autochthonous transmission of Chikungunya have occurred in Italy. The main outbreaks took place in 2007 in Emilia-Romagna and in 2017 in the Lazio and Calabria regions. In the Swahili language, chikungunya means "that which bends" or "contorts." The name describes the symptoms that appear after an incubation period of 2-12 days and manifest with fever and severe joint pain that limits the movements of patients, who tend to curl up in a fetal position. Other symptoms include muscle pain, headache, fatigue, and skin rash. Joint pain is often debilitating, generally lasting a few days but can also extend for several weeks. In most cases, symptoms are mild and recovery is complete, while complications are rare. In some cases, joint pain can persist for months or even years. The mortality rate is less than 1% but can be a serious risk factor for elderly people or those with other ongoing pathologies.
Prevention
Recently, vaccines have been developed for active immunization in individuals aged 12 and older. Vaccination is recommended for those living in or traveling to endemic areas. In any case, it is necessary to consult a doctor or a travel medicine centre before scheduling the vaccination. Prevention consists mainly of avoiding mosquito bites and preventing them from breeding easily. The use of skin repellents, wearing long pants and long-sleeved shirts when outdoors, especially at dawn and dusk, and staying in environments protected by mosquito nets and/or equipped with household insecticide diffusers help reduce the risk of contracting the disease. It is also important to reduce larval breeding sites by frequently emptying containers with stagnant water and treating permanent stagnant water (e.g., manholes) with appropriate larvicide. Travelers returning from a trip to an area where the disease is present are recommended to report the onset of symptoms to their doctor, especially if accompanied by joint pain.Dengue is a disease caused by four very similar viruses (Den-1, Den-2, Den-3, and Den-4) belonging to the Flaviviridae family. It is transmitted to humans by the bite of mosquitoes that have, in turn, bitten an infected person. The main vector is the mosquito Aedes aegypti, although cases transmitted by Aedes albopictus have been recorded. Dengue is widespread in tropical and subtropical areas of Africa, Southeast Asia and China, India, the Middle East, Latin and Central America, Australia, and various areas of the Pacific. It is therefore usually absent in our country where it can be accidentally introduced by travelers who go to countries where this disease is endemic for tourism or work and gives rise to autochthonous cases thanks to the presence on the territory of a competent vector such as the tiger mosquito. Generally, 5-6 days after the mosquito bite, the disease starts with fever, sometimes very high. The fever is accompanied by acute headaches, eye pain, muscle and joint pain, nausea and vomiting, and skin irritations that can appear on most of the body 3-4 days after the onset of fever. There is no specific treatment for dengue, but in most cases, people recover completely. However, the disease can develop in the form of hemorrhagic fever and cause actual collapses and, in some cases, be fatal. Contagion from dengue protects the person only against the virus that caused it but not against the other three.
Prevention
Recently, vaccines have been developed against the different serotypes of the virus. Vaccination is recommended for those living in or traveling to endemic areas. In any case, it is necessary to consult a doctor or a travel medicine center before scheduling the vaccination. Prevention consists mainly of avoiding mosquito bites and preventing them from breeding easily. The use of skin repellents, wearing long pants and long-sleeved shirts when outdoors, especially at dawn and dusk, and staying in environments protected by mosquito nets and/or equipped with household insecticide diffusers help reduce the risk of contracting the disease. It is also important to reduce larval breeding sites by frequently emptying containers with stagnant water and treating permanent stagnant water (e.g., manholes) with appropriate larvicide. Travelers returning from a trip to an area where the disease is present are recommended to report the onset of symptoms to their doctor, especially if accompanied by joint pain.Usutu virus infection is caused by a virus of the Flaviviridae family. It is an infection that mainly affects birds, in which high mortality cases are recorded. The reservoirs of the virus are wild birds, while mosquitoes, mainly ornithophilic ones belonging to the Culex genus, act as vectors. Usutu virus remains primarily confined to a wild bird-mosquito cycle, but in rare cases, it can also be transmitted to humans through the bite of these insects. Transfusions of blood or derivatives and the transplant of infected tissues and organs can be other routes of infection, but it is not transmitted from person to person through simple contact. Mammals, including humans, are accidental and dead-end hosts. Among European birds, die-offs are found in many species, particularly passerines (blackbird, house sparrow, blue tit, great tit, nuthatch, robin, song thrush) but also Strigiformes. Migratory birds play a key role in the spread of the virus outside Africa. In humans, the Usutu virus infections of which there is news are few, but the presence of mild symptoms easily confused with those of other diseases (fever, headache, stiff neck) certainly leads to an underestimation of the number of human cases.