Sindbis Virus - Symptoms and Treatment

What Is the Sindbis Virus?

Sindbis virus, or SINV, is a member of the Togaviridae family that originates from the Alphavirus genus. In 1952, in the delta of the Nile river in Cairo (Egypt), the Sindbis virus was first discovered in Culex mosquitoes. The first reports of human cases came from Uganda in 1961, South Africa in 1963, and Australia in 1967. The virus is associated with Pogota disease in Finland, Ockelbo disease in Sweden, and Karelian fever in Russia. Arthralgia (joint pain), rash, and malaise are the principal signs and symptoms seen in humans. Later, the virus was identified as the root cause of the rash-arthritis syndrome. In several parts of Eurasia, Africa, and Oceania, the Sindbis virus is commonly and persistently discovered in invertebrates and vertebrates. However, Sindbis virus infection has mainly been reported in the northern part of Europe. In northern Europe, the Sinbis virus infection is endemic (when a group of diseases is frequently reported in an area), and its cases appear to occur intermittently.

What Are the Symptoms of Sindbis Virus Infection?

The signs and symptoms of Sindbis virus infection are:

• Although it has not been confirmed, the SINV infection's incubation period is frequently shorter than seven days.

• Maculopapular exanthema (skin rash with fever) that covers the trunk, hand, and legs is seen, and these lesions are frequently itchy.

• Fever.

• Joint pain.

• Pain in wrists, hips, knees, ankles, etc.

• Headache.

• Muscular pain.

• Nausea.

• Malaise (feeling of being unwell).

• The clinical condition in children might manifest without indications of joint pain, and other symptoms are typically mild.

• Infections without symptoms are rather common.

• There have been no cases of death caused by Sindbis virus infection.

• Extra-articular symptoms typically go away after a week or two.

• SINV infection causes persistent joint symptoms in many patients, which can last for months or years and, in rare instances, even progress to chronic arthritis.

Who Is Affected by the Sindbis Virus Infection?

Any person exposed to vector mosquitoes not resistant to SINV is susceptible to infection. The prevalence rates are higher in people aged 30 to 69 in endemic areas. Both men and women are equally susceptible to the virus.

Where Is the Sindbis Virus Infection Common?

In Eurasia, Africa, and Oceania, the Sindbis virus is frequently and continually discovered in invertebrates and vertebrates. However, reports of clinical SINV infection in humans come primarily from Northern Europe, where the virus is widespread and intermittently causes large outbreaks. Instances are sometimes reported from South Africa, Australia, and China. The following nation’s wildlife has been found to contain Sindbis virus or SINV antibodies:

• Austria.

• Belarus.

• Czech Republic.

• Estonia.

• Finland.

• Germany.

• Hungary.

• Italy.

• Moldova.

• Norway.

• Poland.

• Portugal.

• Romania.

• Russia.

• Serbia.

• Sweden.

• Spain.

• Slovakia.

• Ukraine.

• United Kingdom (UK).

Cases are reported annually in Finland, although major epidemics have only happened every seven years. The overall incidence rate was 81 cases per 100,000 people during the 2002 outbreak in North Karelia, a region with a high disease prevalence.

How Is Sindbis Virus Infection Transmitted?

Sindbis virus infection is transmitted through the following ways:

• Reservoir: Experts have theorized that the Sindbis virus cycles between ornithophilic mosquito species and birds. Although spread to other vertebrates may happen, birds may play a significant role in the natural cycle of SINV. It is believed that grouse and passerines act as amplifying hosts for the Sindbis virus. Since the SINV strains from South Africa and Northern Europe are closely related, that these migrating birds may have a role in transporting the virus over great distances.

• Transmission: Although the virus has also been isolated from Aedes and Anopheles mosquitoes, Culex and Culiseta mosquitoes are thought to be the main vectors for SINV transmission to humans. Nearly all human infections in Northern Europe happen in August and September when the main vector species are most common. There is no proof of transfer from person to person. There has been no evidence to support the risk of contracting the virus through blood donation, but the risk cannot be ruled out.

How Can Sindbis Virus Infection Be Prevented?

There are currently no vaccination or preventative medicine available for SINV infection. The use of mosquito nets, sleeping or relaxing in screened or air-conditioned rooms, dressing in clothing that covers the majority of the body, and applying insect repellent are some examples of personal preventive measures to lower the risk of mosquito bites.

How Is Sindbis Virus Infection Diagnosed?

Sindbis virus infection can be diagnosed in the following ways:

• Laboratory Examinations: The enzyme-linked immunosorbent test (ELISA) platform is typically used to identify SINV immunoglobulin M antibodies or IgG seroconversion between paired samples obtained two weeks apart for the laboratory diagnosis of acute SINV infection. Hemagglutination inhibition and immunofluorescence methods can also be used to detect the antibodies. Within eight days of the onset of symptoms, immunoglobulin M antibodies are evident, and IgG antibodies are evident within eleven days. Even six months after infection, more than one-third of the patients still have IgM antibodies, which may be connected to lingering symptoms. Anti-immunoglobulin G antibodies can be detected in a patient lifelong.

How Is Sindbis Virus Infection Treated?

There is no definitive treatment available for the Sindbis virus infection. However, several methods are implied to provide symptomatic relief.

• Antihistamines: Antihistamines are a class of drugs that can be used to treat rashes and itchiness associated with the Sindbis virus infection.

• Analgesics: Non-salicylate analgesics are useful in treating joint pains.

• Corticosteroids: While there is little proof that intra-articular corticosteroids are beneficial, they are occasionally used to treat persistent joint discomfort.

Conclusion:

Sindbis virus infection is caused by the Sindbis virus of the Togaviridae family. The primary vector of the virus is the Culex mosquito. The virus was first discovered in Cairo (Egypt), but the first cases were reported in Northern Europe. The disease is transmitted through a mosquito bite and can only be prevented through precaution and protection. The prognosis of the infection is good, and there has been no death by the Sindbis virus infection to date. However, it is important to consult a doctor when symptoms similar to the Sindbis virus infection are experienced, especially while or after traveling to endemic regions.