How is hepatitis usually transmitted?
Hepatitis is a disorder of the liver. Many doctors in all developing countries are puzzled by the prevention of this disease. And first of all, it is necessary to take into account contact with biological fluids that may contain the unfortunate virus.
Most often, hepatitis is contracted after unprotected sexual intercourse, when using the same syringe, when applying tattoos to the skin, when piercing the earlobes, during a blood transfusion, or during surgery. In addition, a newly born child can also receive hepatitis viruses from its mother.
There is also a considerable chance of contracting hepatitis if the blood of a sick person comes into contact with the skin. The risk of infection increases significantly among those who lead a chaotic lifestyle. There is a high probability of illness in children born in those regions where the incidence rate is quite high.
Health care workers often become infected with hepatitis, as they often have to come into contact with the blood of patients. Well, drug addicts are most susceptible to this disease.
After all, if they have an irresistible desire to get another dose of a narcotic substance, as a rule, everything is indifferent. They will not think ahead and take care of their health. The main thing for them is to get a “high” right here and now. Therefore, they can even use the same needle that has already been used by others.
From all of the above about hepatitis, we can conclude that all methods of transmission of this disease are based on contact with blood. That is why many people fear that a mosquito can become a carrier of the disease, which only does is try to get blood at any cost.
Have there been any cases of infection?
But just as in the case of HIV, there has not been a single case of human infection with hepatitis through insects in world medical practice. If a mosquito were capable of transmitting hepatoviruses, then a global epidemic would have started long ago all over the world. But this, fortunately, does not happen.
The mosquito does not inject blood
The fact that a mosquito, even directly interacting with blood, does not transmit viruses to a healthy person can be explained in the same way as in the case of HIV. After all, when he bites, he injects under the skin of the victim not blood, which is extremely important for him, but his own saliva.
Study: every sixth Russian believes that HIV can be contracted from a mosquito bite
Russians still have a vague idea of how HIV infection is transmitted. According to citizens, it is possible to become infected through household means, through food, through the air and through mosquito bites. These are the results of a Rosstat survey reported by Izvestia.
Every sixth respondent - 17% - believes that HIV is transmitted by mosquitoes, 20% found it difficult to answer. 27% are confident that breastfeeding for HIV is safe, while approximately the same percentage know nothing about it.
11% are afraid to sit at the same table with an HIV-positive person, as they can become infected through food or utensils. 14% do not know whether the infection spreads through this route. Only 15% of survey participants admit that a person with HIV can look completely healthy.
Awareness of HIV is almost independent of age, but educated people know more about methods of transmission and methods of preventing the disease. For example, among respondents with higher education, 87% believe that using a condom reduces the risk of infection. Among people with nine years of education, only 74%.
According to the head of the Federal Scientific and Methodological Center for the Control and Prevention of HIV Infection, Academician of the Russian Academy of Sciences Vadim Pokrovsky, the low level of literacy on the issue of HIV transmission is due to the fact that there is no social advertising in the federal media, although active propaganda is needed to stop the epidemic.
Pokrovsky noted that the virus is not transmitted either at home, through the air, through food, water or mosquito bites. But if an HIV-positive pregnant woman does not take therapy, the risk of giving birth to an infected child ranges from 30 to 50%. Today, the most effective prevention of the disease remains the use of a condom - the risk of infection is reduced by approximately 200 times.
Project coordinator at the association E.V.A. Elena Ivanova added that the low awareness of Russians about how the disease spreads leads to stigmatization of people with HIV infection. Fear of seeking medical help leads to significant deterioration in health, and in some cases, death.
According to the Rospotrebnadzor AIDS Center, at the end of October 2018, more than 1.3 million Russians were infected with HIV, and more than 998 thousand patients lived in the country. The Ministry of Health called these data unreliable. The agency has access to more accurate data on the number of HIV-infected people in Russia, and, according to its information, in 2021, 85,802 cases were identified in the country, and at the end of November 2021 - 71,365.
In 2021, the UN called the HIV situation in Eastern Europe and Central Asia a challenge. The HIV epidemic is growing in this region, which includes Russia. It started with people who inject drugs and has now expanded to the entire population. Russia is the third country in the world in terms of the number of new cases of HIV infection after South Africa and Nigeria.
Let's sum it up
So, we have found out that it is impossible to become infected with HIV through a mosquito bite. HIV is transmitted through blood, and when a mosquito bites, it injects not blood, but saliva. In addition, its proboscis is designed in such a way that it does not allow the blood of the previous victim to mix with the one that the insect is currently biting.
Despite this, when a mosquito bites, it can infect a person with other dangerous diseases: malaria and yellow fever. To reduce the risk of being bitten by mosquitoes, it is necessary to use special repellents that are applied to the body or clothing. Depending on the skin type and age of a person, there are different types of repellents.
If you are in doubt about choosing a product to protect against mosquito bites, ask for advice from a sales consultant in a specialized store.
Can a mosquito transmit AIDS through a bite, do they carry HIV?
Mosquitoes and other blood-sucking insects bite both HIV-infected patients and healthy people alike. However, it is impossible to become infected with HIV through a mosquito bite for the following reasons:
- When a mosquito bites, it injects saliva, not blood. Malaria, some types of fever and other diseases are transmitted through saliva, but HIV is not spread.
- The mosquito's proboscis is designed in such a way that it works on the principle of a valve: blood is sucked in through the proboscis, but does not flow back out.
- A mosquito that has drunk blood will not bite again.
- HIV, entering the body of a mosquito, is not able to reproduce and simply dies.
Surely, after such arguments, you will have no doubt about the question of whether you can get HIV from a mosquito. The answer is negative! So the next time you are bitten by a mosquito, do not panic and run to get your blood tested - HIV infection is not transmitted through an insect bite.
What diseases do mosquitoes carry?
Mosquitoes are insects that suck the blood of humans and vertebrates. They are the most dangerous carriers of human diseases and act as one of the owners of any pathogen.
Why do mosquitoes drink blood?
How can a mosquito be useful?
How do mosquitoes find us in the dark?
Experts' point of view
According to doctors and biologists, mosquitoes carry three main types of diseases:
- malaria - a severe infection widespread in tropical countries, transmitted by Anopheles mosquitoes;
- a number of diseases caused by a microscopic filament worm, which provokes blockage of blood vessels, thrombosis, swelling of the extremities - “elephantiasis”;
- diseases caused by various microbes and viruses: various types of fevers, encephalitis.
Malaria, yellow fever and dengue fever, dysentery, and encephalitis claim more than 40% of lives every year.
Dysenteric amoeba
However, the spectrum of diseases is not static. The list is expanding, adding new forms of infections. For example, diseases transmitted by insects to animals, and from them to humans: avian malaria, tick-borne borreliosis, myxomatosis transmitted from rabbits, hepatitis C virus.
Dysenteric amoeba: can you get infected, yes or no?
Of the particular cases we are considering about the transmission of diseases by mosquitoes through a bite, the transmission of dysenteric amoeba stands out somewhat. Dysenteric amoeba is transmitted mechanically by mosquitoes.
Sitting on excrement, the insect catches particles of bacteria on its paws, which are its causative agents.
If after this the mosquito lands on human skin or food, then there is a risk of getting a gastrointestinal infection.
Symptoms of this infection include bloody diarrhea. However, just under 90% of this infection is asymptomatic and does not require treatment.
The infection, penetrating the intestines, spreads in the colon without being absorbed into the tissues and does not lead to intestinal dysfunction. A person is healthy, but at the same time he is a carrier of infection.
Therefore, he can transmit this disease to other people.
What to do?
To avoid sad consequences, you need to know the nature of the symptoms that develop after insect bites. Precautionary measures taken in a timely manner are of no small importance.
Symptoms
Malaria is accompanied by fever, chills, severe anemia, headache, and muscle weakness. Upon further examination, an enlargement of the liver and spleen is noticed.
Yellow fever occurs with elevated body temperature, accompanied by bleeding in the gastrointestinal tract, abdominal pain, and vomiting.
Please note the condition
The accompanying symptoms of encephalitis are headache, high body temperature, stiff neck muscles, and convulsions.
Preventive actions
When traveling to a region where insect-borne diseases are endemic, you need to take adequate preventive measures:
- use repellents;
- wear loose-fitting clothes, made of light, light fabrics, with long sleeves;
- stock up on a mosquito net.
Remember, if within two years after returning from endemic regions you find signs of an acute illness, you need to contact both a general practitioner and an infectious disease specialist.
HIV infection and other diseases
So, we have found out that you should not be afraid of contracting HIV infection from a mosquito bite, however, this does not mean that you can completely give up on mosquitoes.
Source: https://nzs-rst.ru/vshi/mozhet-li-komar-zarazit-spidom.html
If my partner tests negative for HIV, is he not infected?
Unfortunately, obtaining a false negative result is also possible. If your partner tests negative for HIV and you test positive twice, he or she needs to be tested again. According to information taken from AIDS.gov (an information portal on HIV/AIDS), the likelihood of obtaining a false negative test result depends on the length of time between possible exposure to HIV infection and the time of testing: “Seroconversion takes a certain time to occur. Seroconversion is the production of specific antibodies in response to the appearance of HIV. This process takes from two weeks to six months after infection. The work of the diagnostic test system is aimed at detecting antibodies. Therefore, if you test negative for HIV within three months of your last possible exposure, the CDC recommends testing again three months after your first screening test. A negative result indicates the absence of infection as a result of contacts that occurred more than six months ago. The accuracy of a negative result is certain if you have not been exposed to HIV infection in the past six months.”
Why is coronavirus not transmitted by mosquitoes?
It's easy to think of mosquitoes as tiny flying dirty syringes, carrying droplets of infected blood from person to person. In reality, everything is much more complicated. When a mosquito bites and sucks some of the blood containing the virus, the virus enters the insect's intestines. From there, the virus must infect the cells lining the gut and "escape" to infect the rest of the mosquito's body, spreading to the legs, wings and head.
The virus must then infect the salivary glands before being transmitted in the next bite. This process can take from several days to a week. But time is not the only barrier. The virus must also leave the intestines, travel through the body, and then enter the saliva. Each step in this process can become an impenetrable barrier to the virus. This may be simple for viruses that have adapted to this process, but other viruses will die in the intestines or be excreted from the body. But scientists continue their research.
Related article: Mosquitoes that carry malaria may have been doing so 100 million years ago.
The journal HIV Medicine published a systematic review by a group of British researchers, which summarized data on the risks of HIV transmission through bites and spitting. A total of 742 scientific articles covering these issues were analyzed over more than 30 years.
Let's start with spitting. Everything is clear here - such a transmission route for HIV has not been established, and researchers clearly exclude such a route. This is explained primarily by the properties of saliva, which effectively lyses viral particles.
In rare cases, bites have led to the transmission of HIV infection. Researchers are looking at confirmed cases as well as those that appear plausible. Here are some of them:
A man with primary central nervous system lymphoma bites an emergency worker a couple of weeks before his death. A copious amount of blood was recorded in the mouth of the biter. This happened in the mid-90s, and the person who was bitten received zidovudine monotherapy. Apparently not effective. Moreover, post-exposure therapy was also used for the bitten person in the form of zidovudine monotherapy, but on the 54th day from the bite, seroconversion was recorded. The viral load of the bitten person, as well as the presence of drug resistance mutations, have not been studied.
The CDC described a case of multiple deep bites on a 91-year-old man who received them while attempting to rob a female prostitute. The case dates back to 1995, seroconversion was recorded after 6 weeks, and the genetic relationship of the HIV strains was also confirmed.
A 44-year-old man was bitten in 2010 by his adopted HIV-positive son. As a result of the bite, the man lost his thumbnail. There is no clear evidence as to whether blood was present in the mouth of the person being bitten. The genetic relationship of the HIV strains has been confirmed. The biter had a viral load of 17,163 copies of HIV RNA per ml shortly after the incident.
There have also been two poorly documented cases of HIV transmission to children. In one case, described in a 2006 article, a three-year-old child was bitten by his father, who at the time had bleeding gums as well as extensive tooth decay. It is not known for certain whether this case is related to the transmission of HIV, or whether there were other undocumented episodes, since the man was diagnosed with HIV 3 years after the incident, after which he soon died. Phylogenetic analysis was not performed in this case.
Another case dates back to 1986. A child who received infected blood during cardiac surgery died due to toxoplasma lesions and HIV infection. After his death, family members were tested for HIV, and his brother was diagnosed with HIV infection. Six months earlier, the parents noted an incident in which a deceased brother had bitten another. It is unknown whether the transmission was related to one or another episode that was not noticed and described.
The article also presents a number of cases that the researchers classified as extremely doubtful.
Scientists indicate that the risks of HIV transmission through bites are extremely low, despite the fact that incidents involving bites occur relatively frequently. For example, in the United States, there are more than 600 cases of documented bites of police officers and emergency services personnel per year. A retrospective four-year review of only one emergency department in the UK found a rate of staff bites of at least one every three days. However, over many years of observation there are only isolated recorded and documented cases of HIV transmission. Most of them are characterized by the presence of a significant amount of blood in the mouth of the source of infection during the bite, as well as a significant volume and depth of damage.
Cresswell FV, Ellis J, Hartley J, Sabin CA, Orkin C, Churchill DR. A systematic review of the risk of HIV transmission through biting or spitting: implications for policy. HIV Med. 2021 Apr 23. PMID: 29687590.
