Ticks can transmit pathogens to humans responsible for various diseases such as:
- tick-borne viral encephalitis (TBE, Tick Borne Encephalitis)
- rickettsiosis (Mediterranean spotted fever)
- Lyme borreliosis
- Crimean-Congo haemorrhagic fever (CCHF)
These are zoonoses, meaning diseases transmitted by the bite or sting of a tick.
What is TBE?
TBE (Tick Borne Encephalitis) is a severe acute infection of the central nervous system caused by a flavivirus. About two-thirds of human infections with the TBE virus are asymptomatic. In clinical cases, TBE often has a biphasic course: an initial phase (lasting about 5 days) with nonspecific symptoms (fever, fatigue, headache, myalgia, nausea), followed by an asymptomatic interval of seven days and a subsequent second symptomatic phase involving the central nervous system (meningitis, meningoencephalitis, myelitis, paralysis, radiculitis). Long-term neurological consequences and even death are possible. In addition to being caused by the bite of an infected tick, it can occasionally be caused by the consumption of unpasteurised dairy products.
What is Rickettsiosis?
Rickettsiosis (Mediterranean spotted fever) is an infection caused by bacteria of the genus Rickettsia transmitted by various species of hard ticks, especially Rhipicephalus sanguineus, a common parasite of dogs and other domestic and wild animals such as cattle, sheep, goats, rabbits, and hares.
It presents as an acute febrile illness with varying degrees of severity. At the onset of symptoms, at the site of the tick bite, the typical skin manifestation of the disease may be present, namely an ulceronecrotic lesion a few millimetres in diameter, also known as 'tache noire'.
During the first week of illness, a generalized maculopapular erythema may also be present.
Mediterranean spotted fever generally resolves within a few days with appropriate therapy, but if left untreated, it can cause lethal forms, especially in elderly individuals or those with weakened immune systems.
In Italy, the disease is endemic, as in other Mediterranean and North African countries where, in many of these, there has been an increase in cases in recent years. An adequate preventive action against rickettsioses may consist of carrying out appropriate antiparasitic treatments on animals, particularly domestic ones, with contagion prophylaxis techniques such as isolation and environmental disinfestation.
What is Lyme Borreliosis?
It is a bacterial infection caused by bacteria of the genus Borrelia (Borrelia burgdorferi sensu lato) that can affect various tissues. In the early phase of the disease, following a tick bite, a red skin rash (called erythema migrans) appears, spreading in a ring from the site of the bite. Within a few weeks to a few months after infection, patients may develop neurological, osteoarticular, cardiac, and cutaneous disorders.
The symptoms are fluctuating and can last for months and become chronic. Rare cases of chronicity can evolve into alterations of the central and peripheral nervous system. The ticks that transmit the disease prefer a relatively humid and cool environment (such as pastures and woods).
Wild rodents and other mammals and birds serve as reservoirs for the immature forms of ticks (larvae and nymphs), while deer, horses, and other large mammals are the most common hosts for adult female ticks.
What is Crimean Congo Haemorrhagic Fever?
Crimean Congo Haemorrhagic Fever (CCHF) is one of the most widespread arboviral diseases in the world, found in various parts of Africa, Asia, and Eastern Europe. It is a haemorrhagic fever caused by a virus of the Nairovirus genus that is mainly transmitted through the bite of infected ticks and can cause severe epidemics, with mortality rates ranging from 10 to 40%. The virus that causes this disease circulates in nature among ticks and various domestic and wild species. In animals, the virus is often asymptomatic, while in humans the disease is often severe.
Which ticks are most common in Italy?
In Italy, the ticks to pay particular attention to are two:
- the dog tick (Rhipicephalus sanguineus)
- the wood tick (Ixodes ricinus)
Source:Ministry of Health