Unexplained diarrhoea in HIV-1 infected individuals

Area of Science:

• Virology
• Gastroenterology
• Infectious Diseases

Background:

• Diarrhoea is a common gastrointestinal symptom in untreated Human Immunodeficiency Virus type 1 (HIV-1) infected individuals.
• The aetiology of diarrhoea remains unexplained in a significant proportion of HIV-1 patients despite investigations for enteric pathogens.

Purpose of the Study:

• To identify the causative agents of diarrhoea in HIV-1 infected patients with unexplained symptoms.
• To investigate the role of known and novel enteric pathogens, as well as HIV-1 itself, in causing diarrhoea.

Main Methods:

• Stool samples from 196 HIV-1 infected individuals, including 29 with diarrhoea, were analyzed.
• Enteropathogens and HIV-1 were screened for, alongside a search for unknown viruses using virus discovery cDNA-AFLP and Roche-454 sequencing (VIDISCA-454).

Main Results:

• HIV-1 RNA was detected in stool samples of 66% of patients with diarrhoea versus 45% without.
• While known enteropathogens were identified in 66% of diarrhoea cases, novel viruses (cosavirus, Aichi virus, human gyrovirus, non-A non-B hepatitis virus, IASvirus) were detected but not associated with diarrhoea.
• Enteropathogen-negative cases showed higher HIV-1 RNA shedding (80%) compared to enteropathogen-positive cases (47%), implicating HIV-1.

Conclusions:

• Recently described or unknown pathogens are unlikely causes of unexplained diarrhoea in HIV-1 infected patients.
• Human Immunodeficiency Virus type 1 (HIV-1) is the most probable cause of diarrhoea, likely through its role in intestinal mucosal abnormalities.