There has been a recent positive case of Hantavirus reported in China. The affected individual died due to shortness of breath and pulmonary distress. A Hantavirus is a group of viruses that are transmissible from rodents to humans. It is an RNA-based virus. The main consequences of Hantavirus infection are – HPS (Hantavirus pulmonary syndrome) and HFRS (Hemorrhagic fever with renal syndrome). It is an air-borne infection but is not contagious. HPS and HFRS are among the rarest diseases yet.
Mode of transmission of Hantavirus
Hantavirus is a non-contagious disease. The primary vectors are rodents like mice. Different species of mice, for instance, Deer mice, and rice rats, carry a specific sub-type of Hantaviruses. The rodents are asymptomatic carriers, i.e., they carry the virus but do not show any symptoms of the disease. Hence, they remain unaffected. The virus uses the nutrition and metabolism of the rodents to multiply and finally settle in the feces and urine of the rodent.
Any individual can contract the virus via inhalation of rodent aerosols and any contact with the rodent excreta. The perfect living space for rodents is construction sites, unhygienic surroundings, and basements (less frequently used). They leave behind their feces or urine, and when an individual cleans up the waste, the chances of exposure to the virus increases.
Though it is an air-borne infection, there are no positive cases of human-to-human transmission. However, if a group of individuals living in the same apartments or society is infected, it doesn’t prove human to human transfer; instead, it means they are exposed to the same rodent population.
Origin of Hantavirus
The first case of Hantavirus (1993) was reported in the “four corners” when a person suddenly died due to shortness of breath. Additionally, they encountered more cases with similar sudden deaths due to respiratory complications in the same geographic region. They extracted the tissues from the infected individuals and sent them to the CDC for analysis. In the studies, they found a common link between the patients; and suspected that the infection passed from rodents to humans.
For studies, they trapped various rodents and started further analysis. From a rodent, trapped from the surroundings of an infected patient, they isolated a strain of a common virus. The primary reason behind the outbreak was the favorable conditions and proliferation of mice because the population grew at a considerable rate in the “Four Corners area.”
What is the activity of the virus in humans?
When the virus infects humans during inhalation, it reaches the lungs. It damages the vessels in the lungs and opens pores. The leaky vessels disrupt breathing, causing the pulmonary syndrome. It also interrupts the heart function making it difficult to pump blood throughout the body. Due to the lack of oxygen supply, the cells experience shock and organ failure, eventually resulting in death. Dendritic cells in the respiratory tract facilitate spread to distant organs. The lack of animal models makes it difficult to find the pathogenesis of the virus.
Signs and symptoms of Hantavirus disease
After an incubation period of one to five weeks of the infection, the early symptoms show up. The symptoms include fever, myalgia, and headaches. Other symptoms reported from infected patients are abdominal pain, chills, and dizziness. Late symptoms that appear after four to 10 days of early symptoms include increased severity of coughing and shortness of breath and pulmonary edema.
There is neither a vaccine nor a treatment for the disease. Although the current medication administered is an antiviral drug, Ribavirin, it didn’t give any positive results in HPS. Whereas, its effect on HFRS reduced illness and death. Supportive care is a must. An individual suffering from HFRS needs to undergo immediate dialysis.
Moreover, HPS patients should receive the care within a few days of the symptom appearance; else, it is challenging to treat the condition. They should undergo treatment in intensive care units due to respiratory failure. The mortality rate of the disease is currently 38%. The procedure is usually a few weeks after which the person can go back to live a healthy life.
Diagnosis
Shortness of breath can serve as the first sign of infection. Fever, nausea, diarrhea, myalgia, headache are among others. However, it is essential to share the locality of your home and workplace, which is the most potential place of infection (to define the association with rodents). Special immunology equipment is essential for further analysis. Specialized clinicians analyze the sample to differentiate it from other viruses like Ebola and Marburg (Also cause hemorrhagic fever).
The population localized to the specific endothelial cells and inflammatory cells suggest a favorable adherence for the organism. Human beta 3 integrins are known to confer susceptibility by acting as a critical adhering receptor. The viral G1 and conserved G2 surface glycoproteins mediate the attachment to the receptors. Accumulation is observed in the endothelium capillaries, lymphoid follicles, and lymph nodes. The viral nucleic acids are present in the inflammatory cells.
Molecular and biochemical diagnosis
- High creatinine and low albumin
- Immunolabeling (immunofluorescence assays and enzyme-linked assays)
- Endothelial staining
- Special serologic tests to determine Nucleocapsid protein
- Reverse transcription PCR (Not applicable after the onset of early symptoms)
Preventive measures
- Minimal contact with rodents
- Set up traps
- Clean up spills immediately
- Do not sweep rodent excreta without any precautions
- Dispose of pet food. Do not keep it overnight in the pet bowls. Store the food in rodent-free containers.
Related: Ebola virus: What actually happens in the infected system
