Two weeks ago, Global Times, a state-run Chinese publication, tweeted about the death of a man. He was identified as a migrant worker from the South Western province of Yunnan. Tian was on his way to work, on a chartered bus going to the Shandong Province.
Dr Sumaiya Shaikh, an Australian Neuroscientist living in Sweden, tweeted the following day, “The #Hantavirus first emerged in the 1950s in the American-Korean war in Korea (Hantan River). It spreads from rats/mice if humans ingest their body fluids. Human-human transmission is rare. Please do not panic, unless you plan to eat rats”. Did the quick swatting down of people’s fears of another potential pandemic diminish how deadly the virus is? The Southern Metropolis Daily, a Chinese Newspaper published in the city of Guangzhou, reported that the dead man’s home province, Yunnan, has recorded a total of 1,231 Hantavirus victims from 2015 to 2019.
Are there vaccines for this virus? What are the symptoms? How is it transmitted? Are there measures that can be employed to avoid being infected? What is the fatality rate? These are the unanswered questions from many that could be answered if only the need to avoid global fear had not taken over.
What is Hantavirus?
Hantavirus is an RNA virus transmitted to humans by rodents, causing different kinds of diseases. According to South Korean News Services, Hantavirus is named after the Hantan River in South Korea, where Lee Ho-Wang, a South Korean scientist, first discovered and isolated the virus in 1976.
How is it transmitted?
According to the US Centres for Disease Control and Prevention (CDC), the virus is transmitted by coming in contact with aerosolized dust contaminated with rodent urine, rodent faeces, rodent saliva, and rodent bites (rarely). Scientists believe the virus is mainly transmitted to persons when they breathe in air contaminated by the virus.
Eating foods contaminated by the urine, faeces or saliva of an infected rodent could lead to an infection with the virus. Touching surfaces or items contaminated by rodent urine, faeces or saliva, and then touching the face may lead to the virus entering the mucous membranes of the eyes, nose and mouth.
Hantavirus Pulmonary Syndrome and Hemorrhagic Fever with Renal Syndrome
Hantavirus Pulmonary Syndrome is a severe respiratory infectious disease which manifests as a result of an infection with any Hantavirus subtype. There are 14 subtypes of Hantavirus that have been discovered and identified. According to the Department of Public Health, 9 have been identified in North America and each of these Hantavirus subtypes has distinct rodent hosts.
New World Hantaviruses are those found in North America and are usually the cause of Hantavirus Pulmonary Syndrome. They are Sin Nombre (four corners), Bayou virus, Black Creek Canal Orthohantavirus, Muleshoe virus, New York 1 virus, Andes virus and Seoul virus. These viruses spread by rodents such as the deer mouse, white-footed mouse, rice rat and cotton rat. Seoul virus is the primary cause of HFRS in North America, and the rodents carrying this virus usually appear healthy.
Hemorrhagic Fever with Renal Syndrome is another disease caused by Hantaviruses, and these subtypes are referred to as the Old world Hantaviruses. They are Dobrava, Hantaan, Puumala, and Saaremaa. They spread by rodents such as Norway rats, rodents found in the wild, and those kept as pets globally.
What are the symptoms of Hantavirus Pulmonary Syndrome?
The early symptoms are usually like that of flu. They are fatigue, Fever, muscle aches in the legs, back, hips, and other large muscle areas, abdominal pain, sore throat, loss of appetite, nausea, vomiting, diarrhoea, headache, chills and dizziness.
Late symptoms, about 4 to 10 days of being infected with the virus are coughing, chest pain, and shortness of breath that can become severe with time.
What kind of test is used in the diagnosis of Hantavirus Pulmonary Syndrome?
A serological test is used to diagnose HPS. If positive, then it will show evidence of viral antigen in the tissue by immunohistochemistry. Also, the presence of amplifiable viral RNA sequence in blood or tissue, with a compatible history of HPS is considered diagnostic for HPS.
What is the incubation period of Hantavirus Pulmonary Syndrome?
According to CDC in North America, the incubation period varies from 1 to 5 weeks (7 to 35 days) after the initial exposure to an infected rodent’s urine, faeces, or saliva. According to the LA County Department of Public Health, it is approximately 2 weeks with a range of 3 days to 6 weeks.
How can Hantavirus Pulmonary Syndrome be treated?
According to CDC, there is no definitive treatment for Hantavirus Pulmonary Syndrome at this time, but early detection and medical support from an infectious disease doctor, and proper management in the intensive care unit may help the patient through. According to reports, China developed a vaccine against the virus 20 years ago, and this may have reduced the fatalities in China. The effectiveness of the vaccine is not certain.
What are the preventive measures or control for Hantavirus and the resulting diseases?
CDC recommends environmental hygiene in homes, offices, sites, farms, barns etc. Sealing up holes and cracks, putting rat traps, properly sealing food bags and containers, cleaning up leftover foods that attract rodents, disinfecting possible areas rodents may hide in the environment, wearing hand gloves and nose masks while working in remote areas that may shelter rodents, and in disposing of the carcass of rodents caught in a trap. An anatomist, Femi Olukayode, also suggested laying down poisons, using natural predators like cats in the home, and disposing of rodent nests and potentially infectious wastes with disposable hand gloves and plastic bags.
Is Hantavirus Pulmonary Syndrome contagious?
A case of person-to-person transmission was recorded in Chile and Argentina in 1996 by CDC. Nevertheless, it is rare and there is no substantial evidence that HPS can be contagious, but it is well established that it can be transmitted from rodents to humans.
Is Hantavirus Pulmonary Syndrome a deadly disease?
Yes! It can be fatal. According to CDC, it has an average mortality rate of 38%. This is because it kills about 36 to 40% of patients as it attacks the heart of the victims. Because most persons may not know when they had been exposed to rodents or other transmitting agents, late detection may lead to death.
China developed a vaccine against the virus some 20 years ago, which may have reduced fatalities, according to reports. The effectiveness of the vaccine is not yet established by CDC, and its availability globally is in question. Everyone exposed to rodents or its transmitting agents are at risk of contracting this infectious disease. Mopping up of open areas and surfaces with bleach, clearing out abandoned construction sites and buildings, emptying sewers and dirty drainages, and proper management of waste dumping sites are also effective controls against the transmission and spread of this virus. Hantavirus and the diseases associated with it are not to be swept under the carpet as another one of those viruses. It is deadly and the fatality rate is to be reckoned with. Since it has no established treatment and vaccine yet, proper information on how to manage the spread of the virus is vital. Like the coronavirus, the treatment, for now, is management (supportive care) especially through the period of severe respiratory distress until an approved vaccine is endorsed. The symptoms are being taken care of depending on the extent of the manifestation. Therefore the earlier persons visit their health care professionals on recognising any of the symptoms of the virus, the better.