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SCHISTOSOMIASIS. Pathophysiology, diagnosis, and treatment.
Elliott DE, Division of Gastroenterology, University of Iowa Hospitals
and Clinics, Iowa City, USA., Gastroenterol Clin North Am, 1996
Sep, 25:3, 599-625
Globally, schistosomes infect 1 in 30 people. Tourists travel
to endemic areas, whereas students, workers, and expatriates travel
to nonendemic areas. Physicians around the world need to remain
aware of this common parasitic infection. Pathology results from
parasite eggs that lodge in the intestines and liver. Intestinal
schistosomiasis is most often asymptomatic and presents with occult
gastrointestinal bleeding. Hepatosplenic schistosomiasis develops
insidiously because of cumulative fibrotic injury. Stigmata of
liver failure are absent unless comorbid viral or alcoholic hepatitis
is present. Patients with end-stage hepatosplenic schistosomiasis
die from variceal hemorrhage. Diagnosis of schistosomiasis is
confirmed by finding eggs in stool or biopsy specimens. Antischistosome
antibodies may identify infected tourists returning from endemic
areas. Circulating schistosome antigens distinguish current from
past infections. Praziquantel is the schistosomicidal drug of
choice. Most cases of hepatosplenic schistosomiasis resolve after
effective treatment. Prophylactic propranolol may prevent hemorrhage
in praziquantel-treated patients with high-grade varices. Sclerotherapy
is also efficacious. When necessary, patients with hepatosplenic
schistosomiasis tolerate decompressive surgery well.
Chronic liver disease in the Alexandria governorate, EGYPT,
Mario Angelico, Elil Renganathan, Claudia Gandin, Moustafa Fathy,
M. Cristina Profili, Wael Refai, Adriano De Santis, Ali Nagi,
Gamal Amin, Livio Capocaccia, Francesco Callea, Maria Rapicetta,
Gamal Badr and Giovanni Rocchi , J of Hepatology 1997, vol 26
issue 2( February )
Background/Aims:In Egypt chronic liver disease is customarily
attributed to Schistosoma mansoni infection. Anti-HCV antibodies
are highly prevalent among Egyptian blood donors, yet little is
known about the risk factors, pathogenicity and virological features
of HCV and its association with schistosomiasis. We studied 135
adult patients with chronic liver disease living in the Alexandria
governorate, mostly in rural areas of the Nile Delta.
Methods:Evaluation included abdominal ultrasonography; detection
of anti-HCV antibodies and markers of HBV and HDV infection; HCV-RNA
assay by 5' untranslated region nested polymerase-chain-reaction
and HCV genotyping by a line probe assay; serologic (anti-soluble
egg antigen, anti-SEA) and parasitological examinations for Schistosoma
mansoni infection; and liver biopsy, if not contraindicated.
Results:Ninety-one (67%) patients had anti-HCV and 107 (85%) anti-SEA,
32 (30%) of whom excreted schistosomal eggs in stools. In addition,
21 (16%) patients had HBsAg, 86 (64%) anti-HBc and four (3%) anti-delta.
Thus, many patients had evidence of multiple infections, double
in 66% (anti-HCV and anti-SEA), triple in 33% (anti-HCV HBsAg
and anti-SEA). Based on our diagnostic criteria, 25 (19%) patients
had schistosomal portal fibrosis (anti-HCV positive in eight),
24 (18%) chronic hepatitis (anti-HCV positive in 19), 76 (56%)
cirrhosis (anti-HCV positive in 58) and 10 hepatic tumors (anti-HCV
positive in six). At multivariate analysis, the presence of anti-HCV
was independently associated with previous parenteral anti-schistosomal
therapy, a history of hematemesis and seropositivity for anti-HBc.
Fifty (55%) of 91 anti-HCV positive sera had HCV-RNA, in 41 cases
classified as genotype 4a. Detection of HCV-RNA was associated
with a more severe liver disease and occurred less frequently
in patients with a history of schistosomiasis.
Conclusions:HCV infection with genotype 4a is the main cause of
severe chronic liver disease in Egypt, where it is highly associated
with schistosomiasis.
HEPATITIS C VIRUS INFECTION IN SCHISTOSOMIASIS MANSONI IN BRAZIL.
Pereira LM; Melo MC; Saleh MG; Massarolo P; Koskinas J; Domingues
AL; Spinelli V; Mies S; Williams R; McFarlane IG, Institute of
Liver Studies, King's College Hospital, London, UK., J Med Virol,
1995 Apr, 45:4, 423-8
The involvement of the hepatitis C virus (HCV) in the severity
of liver disease in chronic schistosomiasis was investigated in
215 Brazilian patients with S. mansoni infections, but without
evidence of hepatitis B surface antigen (HBsAg). Forty-three had
hepatointestinal (HIS) and 172 had hepatosplenic schistosomiasis
(HSS), and 135 had compensated (HSSC), and 37 had decompensated
(HSSD) liver disease. Fifty-two (24%) were found to have evidence
of HCV infection (seropositive for anti-HCV antibodies and/or
HCV-RNA). These comprised 35 (95%) of the 37 with HSSD, 16 (12%)
of the 135 with HSSC, and 1 (2.4%) of the 43 with HIS, compared
with only 1 (2%) of 50 control patients without S. mansoni. Testing
of matched liver tissue and peripheral blood mononuclear cells
(PBMCs) from 25 patients (6 HSSC and 19 HSSD) with HCV infections
showed that 17 (68%) had "active" viral infections,
in that negative strand HCV-RNA (the presumed replicative intermediate
of the virus) could be detected in liver and/or PBMCs. Among these
25, negative strand HCV-RNA was found in 16 (84%) of the 19 with
chronic active hepatitis, but in only 1 (17%) of the 6 with mild
or inactive disease (P < 0.01). HCV-RNA was detected in matched
spleen specimens from 9 of 10 patients (all of whom were also
positive in PBMCs), suggesting that the spleen is an important
extrahepatic reservoir of the virus.
CAPILLARIA HEPATICA
History. This 4-month-old female Shepherd cross canine was one
of two stray littermates recovered by the local animal control
agency and vaccinated. The pups developed a cough three days
later and were treated for infectious tracheobronchitis. Within
three weeks the pups became lethargic and anoretic with ataxia
of the hind limbs and facial tremors. The pups were euthanitized.
Gross Pathology. One of the pups was submitted for necropsy.
Grossly the pup was in fair body condition with slightly sunken
eyes. There was marked pulmonary edema and congestion with stable
froth in the tracheobronchial tree. There was marked splenic
congestion. There were multifocal areas of pallor along the hepatic
capsular and cut surface. These foci ranged in size from several
milliliters to 1 cm in diameter.
Contributor's Diagnosis and Comments. Chronic multifocal granulomatous
hepatitis- Capillaria hepatica.
There were multifocal areas of hepatic parenchymal necrosis and
mineralization associated with a mild mixed inflammatory cell
infiltrate, consisting predominantly of mononuclear cells with
small numbers of eosinophils. There were foci which contained
cross sections of nematodes and nematode oocytes, many of which
had operculum. Foci containing nematodes exhibited hepatic necrosis
and suppurative to granulomatous inflammation. Portal infiltrates
consisted of mixed mononuclear cells in association with the hepatic
parasitic infiltration.
Capillaria hepatica is a nematode parasite that inhabits the liver
in the adult phase. Unlike trematodes, this parasite resides
in the hepatic parenchyma. The primary hosts of the adult stage
are rodents. However, infections are also occasionally observed
in dogs. The adult deposits its eggs within the liver and the
eggs escape when the primary host is eaten by a predator. Ingested
eggs pass through the gastrointestinal tract of the predator and
are released into the environment. Mature larvae develop which
are then eaten by a suitable host. In the present case, the pup
was a stray and likely foraging for food before being adopted
by the local animal control agency. Both this pup and its litter
mate were also diagnosed with canine distemper.
AFIP Diagnosis. Liver: Hepatitis, granulomatous and eosinophilic,
multifocal to coalescing, moderate, with aphasmid adults and eggs,
German Shepherd Dog cross, canine, etiology- consistent with Capillaria
hepatica.
Conference Note. Sections are variable; all contain eggs consistent
with Capillaria hepatica and some have cross and tangential sections
of adult worms. Adults and eggs are randomly located due to the
parasite's parenchymal habitat. The eggs do not develop further
unless freed from the liver and exposed to air. Following consumption
of infected liver and fecal passage, or death and decomposition
of the host, the exposed eggs develop infective larvae. Following
ingestion, the eggs hatch in the cecum; larvae migrate through
the intestinal wall and into the liver where they mature. Eggs
are deposited in clusters, are barrel-shaped with bipolar plugs
and have a thick, striated, yellow-brown shell. Adults live for
two months or less, possibly explaining their paucity relative
to the number of eggs present.
Dr. Chris Gardiner, parasitology consultant to the Registry of
Veterinary Pathology, concurred with the etiology and noted that
the nematode is an aphasmid due to the presence of one genital
tube and several hypodermal bands. The worms have two large
hypodermal bands and a smaller ventral band. The bands can be
identified as being vacuolated cells with a nucleus. An additional
feature that may be present in some sections is a stichosome esophagus.
Dr. Gardiner indicated that the eggs are characteristic of C.
hepatica and noted that the bipolar plugs are distinct from the
classical operculum present in trematode eggs. Other histologic
features of the adults include a smooth cuticle, coelomyarian/polymyarian
musculature, a pseudocoelom, and an intestine lined by many uninucleate
cells.
Capillaria hepatica is found in many mammals; it poses a public
health threat to children playing in rat infested areas.
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