The news that researchers discovered that a New Lanjia virus outbreak in 35 people in China It raised another alert in the scientific community this week, but that doesn’t mean there is, at the moment, a real threat to the population.
The study on Langia virus (LayV), published in the New England Journal of Medicine, reports cases that occurred between 2018 and 2022 in the provinces of Shandong and Henan.
The discovery came from routine surveillance (sentinel surveillance) that underwent genetic analysis of samples collected from the throats of patients with fever and a recent history of exposure to animals in eastern China.
Then we found this pathogen whose genetic makeup is made of RNA and belongs to the same family (Paramyxoviridae) as two other known viruses: Hendra and Nipah.
According to the Centers for Disease Control and Prevention (CDC) in the United States, Hendra has a mortality rate of 57%, “of seven known human cases, four have been fatal.”
As for Nipah, between 40% and 70% of infected humans have died, but the death rate has reached 100% in some outbreaks, according to the agency.
A slightly different scenario appears to have occurred with Langia, as the authors did not describe any deaths among the cases analyzed.
The main symptoms were: fever (100%), fatigue (54%), cough (50%), loss of appetite (50%), muscle aches (46%), nausea (38%), headache (35%). Vomiting (35%), accompanied by an abnormality in the level of low platelets (35%), a decrease in the number of white blood cells (54%), a decrease in the function of the liver (35%) and kidneys (8%).
In addition to being from the same family, Hendra, Nipah, and Langya are of the same sex: Henipavirus.
“Of the 5 Henipaviruses identified, Hendra and Nipah viruses are highly virulent emerging pathogens that cause outbreaks in humans and are associated with high mortality rates. Three additional species – rice virus, Ghanaian bat virus and Mojiang virus – are not known to cause human disease,” the Centers for Disease Control and Prevention highlighted before the discovery of Langia, which also happens to be Hennep virus VI.
All viruses are zoonotic, which means that they live in animals. The natural hosts of Henipaviruses are petropod fruit bats, known as flying foxes. In them, the pathogen does not cause disease.
Infection in humans occurs through intermediate hosts, rather than directly from bats. In the case of the Hendra virus, the Centers for Disease Control and Prevention (CDC) describes that infection in people occurred through contact with infected horses after exposure to bat urine.
Nipah is transmitted by human contact with pigs or pig tissue infected with bats.
“Person-to-person transmission of Nipah virus has been reported through close contact (including respiratory droplets) with infected persons. Transmission is facilitated by cultural and hygienic practices in which friends and family care for the sick.” from the United States of America.
Hendra virus outbreaks occurred in Australia between 1994 and 2016, all confined to the northeastern coast of Australia. The World Health Organization (WHO) notes that the seven cases of infection in humans occurred “particularly through close contact during the care or autopsy of sick or dead horses”.
Nipah virus was first identified among pig farmers in Malaysia. It later emerged in Bangladesh, where “an annual outbreak has occurred since then,” according to the World Health Organization. The disease has also been reported periodically in eastern India.
Nipah and Hendra can both develop a condition similar to severe flu. The condition begins with fever, body aches, headache and dizziness.
This could progress to encephalitis [inflamação no cérebro] severe with confusion, abnormal reflexes, seizures, and coma; Respiratory symptoms may also be present. Relapsing or late-onset encephalitis can occur months or years after acute illness,” the CDC notes.
Despite being zoonotic viruses, the history of these three viruses shows that animals living with humans should be kept away from wildlife.
Experts often point to deforestation, as urban areas or farms advance into forested areas, as well as climate change, as a risk for the emergence of new pathogens.
The study authors note that, as with the Hendra virus, there is no report of human-to-human transmission of Langea.
“Tracking nine patients with 15 close family members did not reveal close transmission, but the sample size was too small to determine the human-to-human transmission status of LayV.”
RNA viruses are known for their rapid ability to mutate and adapt to new hosts. It is worth noting that the SARS-CoV-2 virus, which causes Covid-19, was also an animal virus, but in a short time it became effective in transmitting between humans.
Langia’s article ends by warning the scientific community that the discovery “deserves further research to better understand the human disease associated with it.”
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