Page 122 - AIDSBK23C

Page 122

involvement may produce intestinal pseudo-obstruction. Chest radiographs often reveal bilateral
interstitial infiltrates. Diagnosis is best made by identifying the larvae on stool examination, or
by finding larvae in sputum or bronchoalveolar lavage specimens. Serologic testing by enzyme
immunoassay can also be performed, and can be useful in patients with unexplained
eosinophilia, though eosinophilia is often absent in AIDS patients. A prolonged course of
thiabendazole may be useful therapy, but treatment failures are common. Hyperinfection may
respond to ivermectin therapy.[526,527,528]

SCHISTOSOMIASIS.-- The parasites of the genus Schistosoma, particularly S. mansoni
and S. japonicum, may co-infect persons with HIV. Schistosomiasis may exacerbate HIV
infection via activation of a TH2 immune response. Parasites traversing the gut may reactivate
viral replication in latently infected mast cells through multiple Toll-like receptor (TLR)
signaling pathways. S. hematobium involving the urinary tract may spread to the genital tract
where female genital schistosomiasis leads to ulceration of vulva, vagina, and cervix that
increase the risk for sexual transmission of HIV.[529,530]

MYCOPLASMA INFECTIONS AND AIDS.-- In vitro, several Mycoplasma species
have been observed to act synergistically with HIV to increase single-cell lysis of HIV-infected
cells. It is not clear what role Mycoplasma infections play in vivo to produce pathogenic effects.
Urogenital Mycoplasma infections may contribute to the mucosal disruption that facilitates
sexual transmission of HIV. Both M fermentans and M pirium have been found in the peripheral
blood of HIV-infected persons. Both M fermentans and M penetrans have been found in the
urine of patients with AIDS, and M fermentans has been found in association with HIV
nephropathy. The strain of M fermentans associated with HIV infection has sometimes been
labeled the incognitus strain. In addition, M fermentans has been detected in tissues of the
mononuclear phagocyte system (thymus, liver, spleen, lymph node) and in brain. Some cases of
respiratory failure have been linked to M fermentans. Mycoplasma genitalium infection has been
found in up to 10% of HIV infected women, often in association with Neisseria gonorrheae and
Chlamydia trachomatis co-infections. Detection of mycoplasmas is made primarily with
molecular probes to DNA.[531,532]

ZYGOMYCOSIS (MUCORMYCOSIS) AND AIDS.-- Infections with the
Zygomycetes, more commonly seen patients with diabetes mellitus, are infrequent in association
with AIDS, though they can be the initial opportunistic infection. This infection is usually
acquired through inhalation of spores, though direct inoculation via injection drug use is
possible, particularly in cases of dissemination. Sites of involvement are typically the skin,
respiratory tract, and intracranial cavity. One of the most common forms of involvement is
rhinocerebral. Most reported cases have occurred in AIDS patients whose risk factor is injection
drug use. The predisposing factor for zygomycosis of ketoacidosis seen in patients with diabetes
mellitus is absent with AIDS, but the predisposing factor of neutropenia seen in other
immunocompromised patients may be present with AIDS. The CD4 count is usually low. The
clinical course can range from acute fulminant progression over days to an insidious infection
persisting for years. Diagnosis is best made by biopsy to identify the broad, short, branching
non-septate hyphae that stain poorly with special stains such as Periodic acid-Schiff (PAS) and
Gomori methenamine silver (GMS). Culture can be performed, but the yield is not as great, and