Sufficient Evidence of an Association

The evidence from available studies is sufficient to conclude that there is an association. A consistent association has been observed between exposure to a specific agent and a specific health outcome in human studies in which chance and bias, including confounding, could be ruled out with reasonable confidence. For example, several high-quality studies report consistent associations and are sufficiently free of bias, including adequate control for confounding.

The committee concludes that there is sufficient evidence of an association between

  • Brucellosis and

    • Arthritis and spondylitis; arthritis usually is manifest within 12 months of the acute illness, and spondylitis might be manifest later.

    • Hepatic abnormalities, including granulomatous hepatitis.

    • Chronic meningitis and meningoencephalitis.

    • Uveitis.

    • Orchioepididymitis and infections of the genitourinary system.

    • Cardiovascular, nervous, and respiratory system infections.

  • Campylobacter jejuni infection and Guillain-Barré syndrome (GBS) if GBS is manifest within 2 months of the infection.

  • Campylobacter infection and reactive arthritis (ReA) if ReA is manifest within 3 months of the infection; most cases of ReA are manifest within 1 month of the infection.

  • Coxiella burnetii infection (Q fever) and

    • Endocarditis years after primary infection.

    • Vascular infection years after primary infection.

    • Chronic hepatitis years after primary infection.

  • Plasmodium malariae infection and manifestation of immune-complex glomerulonephritis years to decades later.

  • Plasmodium falciparum infection and recrudescence weeks to months after the primary infection, but only in the case of inadequate therapy.

  • Nontyphoid Salmonella infection and ReA if ReA is manifest within 3 months of the infection.

  • Shigella infection and

    • Hemolytic-uremic syndrome (HUS) if HUS is manifest within 1 month of the infection; most cases of HUS are manifest within 10 days of the infection.

    • ReA if ReA is manifest within 3 months of the infection; most cases of ReA are manifest within 1 month of the infection.

  • Active TB and long-term adverse health outcomes due to irreversible tissue damage from severe forms of pulmonary and extrapulmonary TB.

  • Visceral leishmaniasis (kala-azar) and

    • Delayed presentation of the acute clinical syndrome.

    • Reactivation of visceral leishmaniasis in the context of future immunosuppression.

    • Post-kala-azar dermal leishmaniasis (PKDL) if PKDL occurs generally within 2 years of the initial infection.



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