A CD4 cell is a pop in of T cell that has a glycoprotein called CD4 on its surface.
By depleting CD4 cells, the immune function is gradually compromised, increasing the risk of HIV-relatedopportunistic infections.
HIV-Infected CD4 Cell (Close-Up)
Increased magnification of an HIV-infected CD4 cell.
National Institute of Allergies and Infectious Diseases (NIAID)
Maturation is required in order for the virus to become infectious.
Mycobacterium Tuberculosis
A scanning electron micrograph ofMycobacterium tuberculosisbacteria, which causetuberculosis (TB).
TB most often infects the lungs, but can many other parts of the body, as well.
National Institute of Allergy and Infectious Diseases (NIAID)
Since 1993,M.
tuberculosishas been classified by the Centers for Disease Control and Prevention (CDC) as anAIDS-defining condition.
Pneumocystis Jiroveci
Russell K. Brynes/U.S.
National Institutes of Health (NIH)
Centers for Disease Control and Prevention (CDC)
A silver-stained micrograph ofPneumocystis jirovecifungi isolated from a bronchial irrigation.
Pneumocystis jiroveci pneumonia (also known as PCP) is considered an AIDS-defining condition in people with HIV.
P. jiroveciiwas originally classified asP.
National Institute of Allergy and Infectious Diseases (NIAID)
cariniibut was later changed to differentiate it from other forms ofPneumocystisfound in animals.
Candidiasis is common in people with HIV.
Toxoplasma Gondii
Photograph Yale Rosen
A photomicrograph ofToxoplasma gondiifound in the tissue sample.
National Institute of Allergy and Infectious Diseases (NIAID)
The most common neurological signs are speech and motor impairment.
In advanced disease, seizures, meningitis, optic nerve damage, and psychiatric manifestations are often seen.
Toxoplasmosis of the brain is classified by the CDC as an AIDS-defining illness in people with HIV.
National Institute of Allergy and Infectious Diseases (NIAID)
Salmonella
Rocky Mountain Laboratories/NIAID/NIH
A scanning electron micrograph ofSalmonellaenterobacteria invading a cultured human cell.
However, the majority of U.S.Salmonella-related deaths are either among older people or those with severely compromised immune systems.
Coccidioidomycosis is a fungal disease caused byC.
Russell K. Brynes/U.S. Centers for Disease Control and Prevention (CDC)
posadaii, and is commonly known as “valley fever.
Varicella Zoster
A fiery-looking electron micrograph ofVaricella zostervirus.
VZV belongs to the same family of virus as the herpes simplex virus (HSV).
Photograph © Michael Francisco
VZV infection is not considered an AIDS-defining illness.
Cystoisosporiasis has been classified by the CDC as an AIDS-defining illness in people with HIV.
Cryptococcus Neoformans
CDC/Dr.
BSIP/UIG via Getty Images
C. neoformansis one of two fungal species that can cause disease in humans called cryptococcosis.
(The other isC.
Transmission occurs mainly through inhalation of the fungus, which is present in soil and bird droppings.
Photograph © Yale Rosen
Extrapulmonary cryptococcosis has been classified by the CDC as an AIDS-defining illness in people with HIV.
Histoplasma Capsulatum
CDC/Dr.
Libero Ajello
A photomicrograph showing twoHistoplasma capsulatumfungi.
Rocky Mountain Laboratories/NIAID/NIH
H. capsulatumis a fungus that can cause disease in humans called histoplasmosis.H.
capsulatumfungus can be found in soil, bird droppings, and bat guano.
As much as 90% of the population in the eastern and central United States have been exposed toH.
Mercy Hospital Toledo, Ohio/Brian J. Harrington/CDC
capsulatum, with most people experiencing little or no side effects.
Those who do generally have mild, flu-like symptoms that quickly resolve with no lasting impact.
In immune-compromised individuals, histoplasmosis can progress to chronic lung infection, similar in expression to tuberculosis.
National Institute of Allergy and Infectious Diseases (NIAID)
Histoplasmosis has been classified by the CDC as an AIDS-defining condition in people with HIV.
Kauffman CA.Histoplasmosis: a clinical and laboratory update.Clin Microbiol Rev.
2007;20(1):115132. doi:10.1128/CMR.00027-06
Veesler D, Johnson JE.Virus maturation.Annu Rev Biophys.
U.S. Centers for Disease Control and Prevention (CDC)
2017;26(1):1731. doi:10.1016/j.soc.2016.07.010
CDC.People at increased risk for toxoplasmosis.
2017;190:4250. doi:10.1016/j.imlet.2017.07.006
Centers for Disease Control and Prevention.Public Health Image Library.
John AR, Canaday DH.Herpes zoster in the older adult.Infect Dis Clin North Am.
CDC/Dr. Edwin P. Ewing, Jr.
2017;31(4):811826. doi:10.1016/j.idc.2017.07.016
Centers for Disease Control and Prevention.
Warkentien T, Crum-Cianflone NF.An update on Cryptococcus among HIV-infected patients.Int J STD AIDS.
2010;21(10):679684. doi:10.1258/ijsa.2010.010182
CDC/Dr. Libero Ajello
