The transmission mechanism was sexual contact, drugs injection, blood transfusions and mother-to-child. A social stigma was generated. Since then, there has been a great advance in the knowledge of HIV, being one of the best-characterized known viruses, and a large amount of information has been accumulated about its biology, transmission and pathogenesis.
Although there is no cure for HIV infection, effective antiretroviral therapy ARTs can control the virus and help prevent transmission to other people. The first news were released in January when the complete viral genome sequence was published 6 , showing that it was a new coronavirus belonging to the same group as the coronavirus related to the severe acute respiratory syndrome SARS-CoV causing the outbreak from SARS 7 - 9.
From that day on, most countries in the world have suffered the infection and it is not yet controlled. The data source was PubMed and the search terms and strategy were focused on the definition, epidemiology, transmission mechanism, symptomatology and finally treatment and vaccine development.
The results are summarized in a narrative manner. HIV is a virus that belongs to the genus Lentivirus , subfamily Orthoretrovirinae , family Retroviridae. The HIV-1 virion is a spherical particle, with around nm of diameter, that contains two copies of single-stranded RNA together with the enzymatic machinery reverse transcriptase and integrase implicated in its transformation from RNA to DNA in the cytoplasm of the host cell and the subsequent integration of this material into the cell genome proviral DNA The HIV-1 envelope is formed by viral gp41 and gp envelope glycoproteins, with ability to bind to the CD4 surface protein, present in certain cells, including T lymphocytes and mononuclear phagocytic cells.
This union produces a conformational change in the viral glycoprotein that allows its subsequent interaction with one of the chemokine receptors CCR5 and CXCR4 , which act as co-receptors for the virus, allowing its entry into the cell.
Once inside, it will use the enzyme reverse transcriptase to convert its RNA into DNA, which will be later transported to the nucleus and integrated into the cellular DNA.
Consequently, there is a depression of the immune system. If this depression becomes chronic, the patient progresses to AIDS There are estimations that predict 1. The results show that new infections of all ages decreased from a peak of 3. From the start of the pandemic until , 32 million people died from AIDS-related illnesses There are three transmission mechanisms of HIV-1 infection: sexual, parenteral and vertical HIV is found in blood, pre-seminal fluid, semen, vaginal fluids, and breast milk, and is transmitted through direct contact of these fluids with the mucosa or bloodstream of another person.
According to the data available, in Spain, the most frequent transmission mechanism nowadays is sexual, mainly from men who have sexual relations with other men approximately The symptoms generated by HIV infection begin to appear between 2 and 6 weeks after contact with the virus and can be divided into early infection within the first two months after infection or chronic.
During the early or acute phase of infection, infected people present fever, headache, muscle pain, rashes, sore throat and mouth sores, and swollen lymph nodes. These symptoms can be so mild that are almost not noticed 5. In the phase of chronic infection, the virus continues spreading and destroying immune cells, causing immunosuppression. When AIDS occurs, the immune system is already severely damaged, opportunistic infections, neurodegenerative diseases and cancers occur in infected individuals 5.
After the initial discovery of some drugs that had shown high toxicity and scarce benefit zidovudine, didanosine, zalcitabine , in the discovery of a combination therapy, which initially included antiprotease drugs indinavir, saquinavir was such a change that it was possible to significantly reduce mortality.
After , the emergence of new drugs, including integrase inhibitors, has led to significantly less toxicity and excellent tolerance However, HIV persists in the body due to the early establishment of reservoirs, which cannot be eliminated with any of the current antiretroviral regimens Reservoirs are defined as anatomical sites or cells in which HIV infection is persistent and stable allowing competent viruses to replicate under permissive conditions.
The rest of the virus genome encodes four essential structural proteins, namely spike glycoprotein S , small envelope E , matrix M and nucleocapside N Additional accessory proteins interfere with the immune response of the host. Zhou et al. This receptor is expressed in the lung, heart, blood vessels, intestine and kidneys The coronavirus membrane glycoprotein S is the one that binds to the ACE2 receptor on the surface of human cells The S glycoprotein has two subunits, namely S1 and S2 S1 determines the virus-host ratio and cell tropism with the key fusion domain, which is RBD, while S2 mediates the fusion of the virus cell membrane by two tandem domains: heptad repeats 1 HR1 22 and 2 HR2 After the fusion virus-cell occurs, the virus genome is released into the cytoplasm and the RNA translates two polyproteins, pp1a and pp1ab 24 , which encode non-structural proteins and form replication-transcription complexes RTCs in double-membrane vesicles RTCs replicate and synthesize sets of subgenomic RNAs 26 that encode for structural and accessory proteins.
By using cellular endoplasmic reticulum and the Golgi, newly formed RNAs, nucleocapsid proteins, and envelope proteins bind and form new viral particles Finally, the vesicles containing the virions fuse with the cell membrane and the virus goes out to infect new cells. The situation of SARS-CoV-2 infection today, November 7th , according to the WHO, is as follows: 48,, confirmed cases worldwide with 1,, deaths since the start of the pandemic in December Currently, the continent with most cases is America with 21,, confirmed cases and , deaths.
In Europe, the confirmed cases are 12,, with , deaths 4. These characteristics can explain the sudden pandemic spread of the virus The virus is transmitted through the air, mainly due to small drops of saliva from infected people by coughing or sneezing that can reach two meters The transmission is also produced by direct contact with these secretions or by objects contaminated by them 4.
The most common symptoms include fever, cough, and dyspnea. Diarrhea and abdominal pain are also frequent. Although most cases have mild symptoms, in the most severe cases, the infection can cause pneumonia, severe difficulty breathing, kidney failure, and even death 38 , COVID treatment initially included drugs previously used in HIV treatment, such as lopinavir; subsequent studies demonstrated its lack of efficacy Moreover, as in the case of HIV infection, the first antiviral used Remdesivir has shown very limited efficacy 41 , Apart from corticosteroids to decrease cytokine storm 43 , there are no other useful drugs against SARS-CoV-2 infection.
Even though it may seem that these two viruses induced diseases are not very similar among them, they have some important points in common:. HIV can affect anyone, independently of their social status, race, gender, etc.
This can affect people psychologically, making them feel fear, stress or anxiety. Apart from those factors, in COVID, there are others that can make people feel this - the virus is new, there are not known effective antivirals, the disease is more contagious than expected, it can even severely affect young individuals with no previous pathologies, respiratory failure forces hospitalization for many days… In addition, the panic is even increased by the presence of the Internet, over-information, spreading of unfounded rumors, and hyper connectivity in our lives nowadays.
The existence of natural animal reservoirs is another point in common, although they are found in different animals, being non-human primates in the case of HIV, and bats in the case of SARS-CoV Both viruses generate an increase in the production of cytokine, and this is linked to the viral load in the case of SARS-CoV These cytokines are related with secondary complications in infected people. It is well known that in HIV infection, the cytokine release is a chronic mechanism that generates prolonged inflammation.
Sustained inflammatory status has been related with increased intestinal permeability and bacterial translocation, detected in HIV-infected patients. Info Sheet: HIV This info sheet provides basic information about HIV.
Other Resources. Get tailored information about your risk and learn how to protect yourself. Top of Page. More HIV Topics. Follow HIV. Links with this icon indicate that you are leaving the CDC website. Linking to a non-federal website does not constitute an endorsement by CDC or any of its employees of the sponsors or the information and products presented on the website. You will be subject to the destination website's privacy policy when you follow the link.
The McGraw-Hill Companies; Accessed Dec. Sax PE. Acute and early HIV infection: Clinical manifestations and diagnosis. Sax PE, et al. The natural history and clinical features of HIV infection in adults and adolescents.
Ferri FF. Human immunodeficiency virus. In: Ferri's Clinical Advisor Elsevier; Hardy WD, et al. HIV testing and counseling. Oxford University Press; AIDS and opportunistic infections. Centers for Disease Control and Prevention. Pollack TM, et al. Primary care of the HIV-infected adult. John's Wort.
Natural Medicines. HIV Basics. HIV treatment as prevention. Human immunodeficiency virus HIV infection: Wasting syndrome. Mayo Clinic; Mahmood M expert opinion. Mayo Clinic.
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