Can Parasitic Infections Influence Type 2 Diabetes Development?
Parasitic helminth infections do not cause Type 2 Diabetes Mellitus (DM2), but rather appear to protect against it by inducing immunomodulatory effects that reduce inflammation and improve insulin sensitivity. 1, 2
Evidence for Protective Effects of Parasites
The relationship between parasites and DM2 is inverse—parasitic infections, particularly helminths, appear to reduce diabetes risk rather than cause it:
Schistosoma and geohelminth infections lower the risk of type 2 diabetes, with recent evidence from Tanzania showing that Schistosoma infection was associated with higher beta cell function. 1
Helminth-induced immunomodulation prevents diabetes onset and ameliorates insulin sensitivity by inducing type 2 and regulatory immune responses that counteract the pro-inflammatory state crucial for diabetes development. 2
This protective effect is offset in specific populations: Schistosoma and geohelminth infections were associated with reduced beta cell function among people living with HIV (PLWH) and antiretroviral therapy (ART)-naive individuals. 1
Recognized Infectious Causes of Diabetes
The established infectious etiologies of diabetes are viral, not parasitic:
Certain viruses have been associated with β-cell destruction, including congenital rubella. 1
Hepatitis C infection is associated with a ~1.7-fold increased risk for type 2 diabetes compared with non-infected control groups. 1
Human herpesvirus 8 infection is strongly linked to type 2 diabetes, particularly ketosis-prone type 2 diabetes, and can directly infect human pancreatic beta cells, causing low insulin secretion rather than decreased insulin sensitivity. 1
Mechanistic Understanding
The protective mechanism of helminths operates through immunomodulation:
Parasitic helminths modulate the host immune system and induce type 2 as well as regulatory immune responses. 2
Since pro-inflammatory immune responses are crucial for the onset of both type 1 and type 2 diabetes, helminth-induced immunomodulation may prevent diabetes onset. 2
This aligns with the "hygiene hypothesis"—reduced exposure to pathogens in industrialized countries correlates with increased diabetes incidence, suggesting environmental pathogen exposure may be protective. 2
Clinical Implications
When evaluating diabetes etiology, consider:
Infections increase diabetes risk through inflammation and immune dysfunction, not through direct parasitic causation—patients with diabetes have increased susceptibility to bacterial and viral infections due to immune suppression and hyperglycemia. 3, 4, 5
The primary recognized infectious causes of diabetes are viral (rubella, hepatitis C, Human herpesvirus 8), not parasitic. 1
Parasitic helminth infections represent a potential protective factor against diabetes development, not a causative agent. 1, 2