How are hantavirus infections spreading globally? Experts issue warnings

Infectious Diseases and Clinical Microbiology Specialist Prof. Dr. Meral Sönmezoğlu provided information about the virus following recent hantavirus cases detected in certain regions. Sönmezoğlu stated that hantaviruses are carried by rodents and some insectivorous mammals, and that the primary route of transmission is through the urine, feces, and saliva of infected animals. Human-to-human transmission of the virus remains very limited.

It is known that there are approximately 40 species in the hantavirus family; 22 of these can cause disease in humans. Each hantavirus species maintains its circulation in nature in association with a specific rodent species. The virus was discovered in 1978 around the Hantaan River in Korea and takes its name from there. In fact, the disease was first observed among American soldiers during the Korean War; it was called "Korean Hemorrhagic Fever" because it caused fever, bleeding, and kidney failure. During the war years, thousands of soldiers fell ill, and hundreds lost their lives.

CLINICAL PICTURE AND SYMPTOMS IN HANTAVIRUS INFECTIONS

Hantaviruses manifest in two main ways depending on the type of virus and regional differences. Hantavirus Cardiopulmonary Syndrome (HCPS), which is common in the Americas, generally affects the respiratory system and stands out with cases that rapidly become severe. Fluid accumulation in the lungs and circulatory problems accompany the clinical picture. The clinical picture more commonly encountered in Europe and Asia is Hemorrhagic Fever with Renal Syndrome (HFRS), which progresses with kidney failure. Low blood pressure, a tendency to bleed, and kidney damage are prominent in these patients. Cases seen in Turkey are mostly characterized by kidney involvement.

Prof. Dr. Sönmezoğlu stated that hantavirus cases reported in Turkey generally appear in the HFRS form and that the number of cases can increase due to occupational risks such as agriculture, forestry, and animal husbandry. People working in areas contaminated by rodents and those cleaning closed, poorly ventilated spaces for long periods are particularly at risk.

TRANSMISSION AND PREVENTION METHODS

Hantavirus infection mostly develops as a result of inhaling viruses shed into the environment through the urine, feces, and saliva of rodents. Walking in or cleaning contaminated areas increases the risk of transmission. Although rare, transmission can occur through rodent bites. While human-to-human transmission is almost never seen worldwide, very rare cases have been reported only for the Andes virus type in the Americas, and these have been limited to close contact.

The incubation period of the infection varies between 1 and 8 weeks after exposure to the virus. Initially, flu-like symptoms such as fever, muscle aches, and headaches, as well as abdominal pain, nausea, and vomiting, may occur. In the later stages of the disease, pulmonary edema, severe respiratory distress, or kidney failure may be observed.

Diagnosing the disease can sometimes be difficult because its symptoms resemble those of many other viral infections. For this reason, information such as a history of contact with rodents, occupation, and travel history is of great importance. Methods such as antibody tests or PCR are used for diagnosis, but laboratory work requires high biosafety.

There is currently no approved specific antiviral drug or vaccine for hantavirus infection. The treatment principle is based entirely on supportive measures: respiratory support for patients who develop shortness of breath, monitoring of fluid-electrolyte balance, and, when necessary, monitoring of kidney functions. The chances of recovery increase for patients who seek hospital care early and receive the necessary medical intervention.

An estimated 10,000 to 100,000 hantavirus cases are reported annually worldwide. The highest number of cases is found in China, South Korea, and North-Central Europe. Conversely, although the number of patients in the Americas is lower, the course of the disease is more severe and mortality rates are higher. While mortality rates in Europe and Asia range between 1 and 15 percent, this rate can reach 20-50 percent for the Americas. In Turkey, the number of reported hantavirus cases has ranged between 4 and 58 since 2009.

The most effective way to protect against the disease is to limit contact with rodents and presence in infected areas. Prof. Dr. Sönmezoğlu offered the following recommendations on this subject: "Living spaces must be kept clean. Rodent entry must be prevented. Food must be stored safely. Dust formation should be avoided during cleaning. Contaminated areas should be moistened before cleaning. Attention must be paid to hand hygiene."