TOPIC

Infectious diseases, HIV

HIV/AIDS

The Italian National Institute of Health (ISS) is at the forefront in the fight against infectious agents which, constantly changing over time, make it necessary the frequent updating  of priority actions.

The ISS implements surveillance, prevention and control measures against emerging diseases such as those deriving from the spread of antibiotic-resistant biological agents commonly found in hospital environment, and those transmitted by vectors, such as chikungunya, dengue and West Nile.

Vaccine preventable diseases, although they have been reduced due to effective interventions, represent a significant burden of diseases which require to maintain a high level of attention.

Viral hepatitis and sexually transmitted infections, as human papillomavirus (HPV) infection, are a paradigmatic example of how chronic infections can result in degenerative diseases and even cancers. A vaccine is available for hepatitis B virus (HBV) and HPV infection.

Infectious diseases include also neglected tropical diseases, as intestinal parasitosis and echinococcosis, found in many parts of the world.

With regard to HIV / AIDS, the antiretroviral therapy (ART), although it has saved millions of lives, does not eliminate the HIV from the body nor restore the immune system completely back to normal. Furthermore, it has limited effects if started late or not taken regularly.

In order to stop the HIV epidemic and assure those living with the infection (about 38 million people with HIV / AIDS in the world, including 20.6 million in Africa) better quality of life and life expectancy, the ISS develops surveillance, prevention and treatment strategies, working in cooperation with the National Health Service (SSN), Regions, developing countries and international bodies.

General aims of ISS research activities on HIV/AIDS include:

  • study and surveillance of the spread of HIV and its variants, and of co-infections in general and vulnerable populations
  • study of the mechanisms of infection, of development of AIDS and associated diseases
  • facilitating ART adherence by improving its effectiveness and reducing its side effects
  • development of new strategies capable of preventing infection, reducing its progression and enhancing the effectiveness of ART, in particular preventive and therapeutic vaccines
     

HIV infection and co-infections with HBV and HCV

How HIV infection and associated HBV and HCV co-infections impact "fragile" populations, evolve and spread in Italy 

Continuous surveillance of HIV infection and HBV and HCV co-infections, in "fragile" populations and in the general population, is a key tool to implement timely public health interventions in order to limit  spread of these infections and, at the same time, optimize and customize effective preventive and therapeutic strategies. CNAIDS is committed to establishing a surveillance system for HIV variants. 

The HIV virus is characterized by an extensive genetic variability, responsible for the extreme diversification of circulating viruses in clades, which vary according to geographical areas. Subtype B is predominant in the USA, Europe, and Australia. Subtype C is widespread in the Indian Peninsula, Southern Africa, and the Horn of Africa and, alone, is responsible for about 50% of infections, worldwide. Subtype A is predominant in Eastern Europe and Central Asia. Finally, subtype D is present in Eastern Africa, south of the Sahara. The remaining clades have a local spread in different geographical regions, especially in Western Sub-Saharan Africa and Asia, where several clades are present. The infection with various subtypes also generates recombinant forms (CRF) whose number is constantly increasing, adding further complexity to the heterogeneity of HIV that appears significantly higher than initially thought. 

The global distribution of HIV strains is constantly evolving, fueled by trade, travel, military missions and migration. In Western countries, including Italy, infections supported by non-B subtypes are constantly increasing. As HIV continues to circulate globally, the current geographical distribution is likely to change in the short to medium term. The presence of numerous subtypes and CRFs can have an important impact on the public health. In fact, variants of the various viral subtypes and CRFs may show different capacities of transmission, avoidance of host immune response, resistance to antiretroviral therapy and disease progression. In addition, the genetic variability of the virus can have an impact on the sensitivity of the tests used for laboratory diagnosis and viral load measurement in the blood. 

“Fragile" populations are more exposed to HIV infection and co-infections by HBV and HCV (hepatitis viruses), which are also genetically variable and present, like HIV, with numerous genetic forms and different prevalence in the different geographic areas of the world. 

In this context, CNAIDS promoted a national programme for monitoring the HIV, HBV and HCV genotype variability of viruses circulating in the general Italian population and in “fragile” populations, such as immigrants and prisoners, as suggested by the European Union and the WHO.