Liver abscess and schistosomiasis. A new association

Fatal human eosinophilic meningo-encephalitis caused by CNS co-infection with Halicephalobus gingivalis and West Nile virus

The saprophytic nematode Halicephalobus is a rare cause of fatal human meningo-encephalitis, and West Nile virus is neurotropic flavivirus implicated in a variety of clinical neurologic syndromes. Here we report a case of rapidly progressive CNS encephalopathy and death. Serologic, immuno-histochemical, histopathologic and nucleic acid studies demonstrate the presence of active Halicephalobus and West Nile virus in the CNS tissue. This is the first reported case of co-infection with these neurotropic pathogens.

Revisiting the concept of hepatosplenic schistosomiasis and its challenges using traditional and new tools

Different aspects of hepatosplenic schistosomiasis are revisited here. Manson's schistosomiasis causes periportal fibrosis and portal hypertension in approximately 6% of infected subjects, usually with preservation of their hepatic function. The assessment of liver involvement is of major importance in determining the prognosis and risk of complications from schistosomiasis, such as upper digestive bleeding secondary to variceal rupture. For many years, the diagnosis of hepatosplenic schistosomiasis and liver fibrosis was made by abdominal palpation and the finding of liver and/or spleen enlargement. However, there is no consensus regarding the clinical parameters of the liver and spleen to be considered in this physical evaluation. For the last three decades, abdominal ultrasound (US) has become the best imaging technique to evaluate liver fibrosis caused by schistosomiasis mansoni. However, US is a subjective procedure and is therefore examiner-dependent. Magnetic resonance imaging (MRI) findings have provided valuable information in addition to ultrasound and clinical examination. The combination of a comprehensive history and physical examination, basic laboratory tests (a stool examination for Schistosoma mansoni eggs and a blood cell count), biomarkers for liver fibrosis/portal hypertension and imaging methods seem to offer the best approach for evaluating patients with this disease. In situations where research is involved or in patients with severe disease, MRI may be considered.

Coinfection of Schistosoma (Trematoda) with bacteria, protozoa and helminths

This review examines coinfection of selected species of Schistosoma with bacteria, protozoa and helminths and focuses on the effects of the coinfection on the hosts. The review is based mainly on tables that contain the salient information on the coinfecting organisms in vertebrate hosts. Further explanation and clarification of the tables are given in the text. A table is also provided that gives synoptic information on the 37 species in the 19 genera considered in this review. Coinfection studies with Schistosoma species and the other organisms were considered in six tables plus the accompanying text. Considerations of the Schistosoma interactions with another species of organism include studies on coinfection with Plasmodium, with protozoa other than Plasmodium; with Salmonella, with bacteria other than Salmonella; and with Fasciola, with helminths other than Fasciola. Numerous factors were found to influence the effects of coinfection on the vertebrate host, including organisms and hosts used in the studies, order and time interval between the first and the second infection, studies on natural versus experimental hosts, dosage of the infectious agents, strains and pedigrees of the parasites, age of hosts at time of exposure to the infectious agents and age of hosts at the time of necropsy. Overall, a prior infection with Schistosoma, particularly a patent infection, often has an effect on the subsequent infection by a protozoan, bacterium or other helminth. In relatively few cases, a prior infection with Schistosoma decreased the severity of the subsequent infection as with Helicobacter pylori, Fasciola hepatica, Echinostoma or Plasmodium, the latter only exhibiting this behaviour when coinfected with Schistosoma haematobium. More often, however, a prior infection with Schistosoma increased the severity of the second infection as with Leishmania, Toxoplasma gondii, Entamoeba histolytica, Staphylococcus aureus or Salmonella. In some of these coinfection studies, the increased severity of the subsequent infection was associated with a specific, prolonged form of the disease in humans, which has implications for patient treatment and recovery. Additional research is needed, particularly on Schistosoma coinfections which currently have a small body of research and are current problems in human populations. Examples of such Schistosoma interactions include the genera of Mycobacteria, Leishmania, Staphylococcus, Necator and Strongyloides. Hopefully, future studies will elucidate valuable new information on the interesting subject of coinfection of Schistosoma with other organisms.

Acute schistosomiasis mansoni: revisited and reconsidered

Acute schistosomiasis is a systemic hypersensitivity reaction against the migrating schistosomula and eggs. A variety of clinical manifestations appear during the migration of schistosomes in humans: cercarial dermatitis, fever, pneumonia, diarrhoea, hepatomegaly, splenomegaly, skin lesions, liver abscesses, brain tumours and myeloradiculopathy. Hypereosinophilia is common and aids diagnosis. The disease has been overlooked, misdiagnosed, underestimated and underreported in endemic areas, but risk groups are well known, including military recruits, some religious congregations, rural tourists and people practicing recreational water sports. Serology may help in diagnosis, but the finding of necrotic-exudative granulomata in a liver biopsy specimen is pathognomonic. Differentials include malaria, tuberculosis, typhoid fever, kala-azar, prolonged Salmonella bacteraemia, lymphoma, toxocariasis, liver abscesses and fever of undetermined origin. For symptomatic hospitalised patients, treatment with steroids and schistosomicides is recommended. Treatment is curative in those timely diagnosed.

Simultaneous occurrence of brain tumor and myeloradiculopathy in schistosomiasis mansoni: case report

Simultaneous occurrence of brain tumor and myeloradiculopathy in cases of Manson's schistosomiasis have only rarely been described. We report the case of a 38-year-old man who developed seizures during a trip to Puerto Rico and in whom a brain tumor was diagnosed by magnetic resonance imaging: brain biopsy revealed the diagnosis of schistosomiasis. He was transferred to a hospital in the United States and, during hospitalization, he developed sudden paraplegia. The diagnosis of myeloradiculopathy was confirmed at that time. He was administered praziquantel and steroids. The brain tumor disappeared, but the patient was left with paraplegia and fecal and urinary dysfunction. He has now been followed up in Brazil for one year, and his clinical state, imaging examinations and laboratory tests are presented here.

Genital schistosomiasis mansoni: tubal tumor and parietal peritoneum involvement diagnosed during laparoscopy

Female genital schistosomiasis is not uncommon in endemic areas for schistosomiasis, but there are few reports in the Brazilian medical literature. Here, we describe the case of a 31-year-old woman with lower abdominal pain who was diagnosed as presenting a fallopian tube tumor caused by Manson's schistosomiasis. The diagnosis was delayed because her symptoms were considered nonspecific. Involvement of the parietal peritoneum of the ovarian fossa was observed during laparoscopy and confirmed by histological analysis. The left tube and the tumor were excised and schistosomiasis was treated with praziquantel. She presented a full recovery and options for future reproduction are under evaluation.

Update on eosinophilic meningoencephalitis and its clinical relevance

Eosinophilic meningoencephalitis is caused by a variety of helminthic infections. These worm-specific infections are named after the causative worm genera, the most common being angiostrongyliasis, gnathostomiasis, toxocariasis, cysticercosis, schistosomiasis, baylisascariasis, and paragonimiasis. Worm parasites enter an organism through ingestion of contaminated water or an intermediate host and can eventually affect the central nervous system (CNS). These infections are potentially serious events leading to sequelae or death, and diagnosis depends on currently limited molecular methods. Identification of parasites in fluids and tissues is rarely possible, while images and clinical examinations do not lead to a definitive diagnosis. Treatment usually requires the concomitant administration of corticoids and anthelminthic drugs, yet new compounds and their extensive and detailed clinical evaluation are much needed. Eosinophilia in fluids may be detected in other infectious and noninfectious conditions, such as neoplastic disease, drug use, and prosthesis reactions. Thus, distinctive identification of eosinophils in fluids is a necessary component in the etiologic diagnosis of CNS infections.

Pyogenic liver abscess in patients with schistosomiasis mansoni

Schistosomiasis mansoni has been described as a predisposing factor for pyogenic liver abscess formation. Previous experimental studies have shown that acute schistosomiasis concurrent with Staphylococcus aureus bacteremia favors the colonization of the liver by the bacteria, and subsequent pyogenic liver abscess formation. In addition, clinical studies and case reports have demonstrated the association of schistosomiasis mansoni with pyogenic liver abscesses. We describe a Brazilian patient with chronic schistosomiasis mansoni who developed recurrent pyogenic liver abscesses due to Pseudomonas aeruginosa. The authors review the clinical, diagnostic and treatment aspects of patients with schistosomiasis and pyogenic liver abscess reported in the medical literature.

Alteration in the endogenous intestinal flora of swiss webster mice by experimental Angiostrongylus costaricensis infection

The association between worm infections and bacterial diseases has only recently been emphasized. This study examined the effect of experimental Angiostrongylus costaricensis infection on endogenous intestinal flora of Swiss Webster mice. Eight mice aging six weeks were selected for this experiment. Four were infected with A. costaricensis and the other four were used as controls. Twenty eight days after the worm infection, all mice in both groups were sacrificed and samples of the contents of the ileum and colon were obtained and cultured for aerobic and anaerobic bacteria. In the mice infected with A. costaricensis there was a significant increase in the number of bacteria of the endogenous intestinal flora, accompanied by a decrease in the number of Peptostreptococcus spp. This alteration in the intestinal flora of mice infected by the nematode may help to understand some bacterial infections described in humans.

Intestinal nematodes and pulmonary tuberculosis

We report a significantly higher prevalence of intestinal nematodes in patients with pulmonary tuberculosis (TB) compared to a matched control group: 33/57 (57.8%) in patients with TB and 18/86 (20.9%) in the control group; OR = 5.19; 95% CI = 2.33-11.69; p = 0.000). When TB patients eosinophilia was also significantly higher among those with intestinal parasites (69.8%) compared to those without this condition (45.6%). We hypothesized that the immune modulation induced by nematodes is a factor that enhances TB infection/progression and that eosinophilia seen in TB patients is a consequence of helminth infection.

Nematode infections are risk factors for staphylococcal infection in children

Nematode infection may be a risk factor for pyogenic liver abscess in children and we hypothesized that the immunomodulation induced by those parasites would be a risk factor for any staphylococcal infection in children. The present study was designed to compare, within the same hospital, the frequency of intestinal nematodes and Toxocara infection in children with and without staphylococcal infections. From October 1997 to February 1998, 80 children with staphylococcal infection and 110 children with other diseases were submitted to fecal examination, serology for Toxocara sp., evaluation of plasma immunoglobulin levels, and eosinophil counts. Mean age, gender distribution, birthplace, and socioeconomic conditions did not differ significantly between the two groups. Frequency of intestinal nematodes and positive serology for Toxocara, were remarkably higher in children with staphylococcal infections than in the non-staphylococcal group. There was a significant correlation between intestinal nematodes or Toxocara infection and staphylococcal infection in children, reinforced by higher eosinophil counts and higher IgE levels in these children than in the control group. One possible explanation for this association would be the enhancement of bacterial infection by the immunomodulation induced by helminth infections, due to strong activation of the Th2 subset of lymphocytes by antigens from larvae and adult worms.

Schistosomiasis mansoni is associated with pyogenic liver abscesses in the state of Minas Gerais, Brazil

The association between pyogenic liver abscesses and schistosomiasis has been confirmed by clinical and experimental studies. In this retrospective study of 78 patients with pyogenic liver abscesses the association with schistosomiasis has been investigated. Pyodermitis, a known focus of bacteremia, was observed in 19 patients (24%). Blood eosinophilia was observed in 30 patients (39%). Staphylococcus aureus was cultured from abscesses in 17 out of 38 patients (45%). Forty-one out of 57 patients (53%) had stool examination. Schistosoma mansoni was the main parasite identified. Eggs of S. mansoni were also identified in liver biopsies in 7 out of 19 patients who did the exam. The large number of young patients with liver abscesses described here is different from what has been observed in developed countries. This clinical study provide support for the concept that granulomas of S. mansoni in the liver are foci for colonization with S. aureus, which in presence of staphylococcal bacteremia can form liver abscesses.

Pyogenic abscesses and parasitic diseases

Parasitic diseases which during their course in the host switch the immune system from a T helper 1 to a T helper 2 response may be detrimental to the host, contributing to granuloma formation, eosinophilia, hyper-IgE, and increased susceptibility to bacterial and fungal infections. Patients and animals with acute schistosomiasis and hyper-IgE in their serum develop pyogenic liver abscess in the presence of bacteremia caused by Staphylococcus aureus. The Salmonella-S. mansoni association has also been well documented. The association of tropical pyomyositis (pyogenic muscle abscess) and pyogenic liver abscess with Toxocara infection has recently been described in the same context. In tropical countries that may be an interesting explanation for the great morbidity of bacterial diseases. If the association of parasitic infections and pyogenic abscesses and/or fungal diseases are confirmed, there will be a strong case in favor of universal treatment for parasitic diseases to prevent or decrease the morbidity of superinfection with bacteria and fungi.

Human toxocariasis and pyogenic liver abscess: a possible association

OBJECTIVES

To study the role of human toxocariasis in the pathogenesis of pyogenic liver abscess.

METHODS

We compared the serology for toxocariasis and serum levels of IgE in 16 patients with pyogenic liver abscess to those in 32 matched (age and gender) controls to define the possible association between these two entities.

RESULTS

The serology for toxocariasis was positive in 10 of 16 patients compared with 4 of 32 controls. The relative odds and 95% confidence interval (conditional logistic regression), comparing cases and matched controls, was significant (1.4; 95% confidence interval, 1.1-1.7) for Toxocara serology. Regarding IgE serum levels, there was no difference between cases and controls.

CONCLUSIONS

Human toxocariasis can be one of the predisposing causes of pyogenic liver abscess, especially in tropical countries in which this parasitic disease is common. Treatment of human toxocariasis may prevent morbid complications like hepatic abscess and should be considered in patients with clinical and/or serological evidence of Toxocara infection.

Schistosoma mansoni: assessment of morbidity before and after control

The literature on the assessment of morbidity due to Schistosoma mansoni infection is updated. Imaging techniques such as ultrasonography, echodoppler cardiography, computerized tomography (CT scan) and magnetic resonance imaging (MRI) introduced a new perspective, and expanded our knowledge on morbidity. Three well-defined syndromes caused by schistosomiasis mansoni have been described: the stage of invasion, acute schistosomiasis (Katayama fever), and chronic schistosomiasis. Complications of the acute and chronic syndromes have also been reported: pulmonary hypertension, neuroschistosomiasis, association with Salmonella, association with Staphylococci, viral hepatitis B, glomerulonephritis. In most individuals with hepatosplenic schistosomiasis the spleen is increased in size. Hepatosplenic schistosomiasis can, however, occur without splenomegaly. The definition of hepatosplenic schistosomiasis in endemic areas as the finding of S. mansoni eggs in the stools in an individual with hepatosplenomegaly is not satisfactory anymore. Many aspects of morbidity are expected to change after schistosomiasis control. Some are expected to change quickly (worm burden, Salmonella bacteremia, hepatosplenic schistosomiasis in children) whereas others shall remain for years (pulmonary hypertension, glomerulonephritis, neuroschistosomiasis). Intestinal schistosomiasis in individuals with low worm burdens is very difficult to diagnose and therefore laborious to control.

Pathology of pyogenic liver abscess in children

Little is known about preexisting lesions in livers of children with pyogenic liver abscess (PLA). Study of these lesions may elucidate possible predisposing factors for the disease. In Vitória, state of Espirito Santo, Brazil, PLA in children is frequently associated with helminthic infections and eosinophilia. We hypothesize that nematode infection with larvae migrating through the liver is a predisposing factor for PLA, because the infection induces immunomodulation and likely trapping of bacteria in liver granulomas. In this report, we describe observations of 22 cases of PLA in children studied at autopsy (16 cases) or in surgical biopsies (6 cases), including 17 boys and 5 girls ranging in age from 1 to 13 years (mean 4.6 years, median 3.5 years). Multiple abscesses in both lobes were found in 13 cases and a single abscess was found in the right lobe in 10 cases. All cases showed histologically classical pyogenic inflammation without morphological evidence of amoebiasis. In six cases there were granulomas similar to those caused by larva migrans visceralis (from Toxocara or other nematodes) in liver tissue not affected by the abscess. Nematode antigens in central areas of necrosis of granuloma in all six cases and fragments of a larva, possibly of Toxocara, were found on samples immunohistochemically stained with polyclonal anti-Toxocara antibodies. There were numerous eosinophils in abscesses with Charcot-Leyden crystals. Eosinophils were found frequently in portal triads far from the abscess wall. In four cases, in which bile duct ascariasis was found, worms were noted in the bile ducts, and eggs were found in liver parenchyma surrounding the abscess in two cases. Foreign-body granulomas were found in one case in which penetrating trauma was the cause of abscess. In one case there was one histiocytic granuloma whose origin was not determined. The observation of six cases of granuloma similar to larva migrans visceralis (or produced by other nematode larva) in liver tissue not directly affected by the abscess supports the hypothesis that helminth infections with larva migrating through the liver are a predisposing factor for pyogenic hepatic abscess in children.

[The association between human toxocariasis and pyogenic abscesses]

The association between hepatic abscesses and schistosomiasis mansoni was confirmed by clinical and experimental studies. Other parasites may cause systemic immunologic changes and local structural alterations in the affected organs that can facilitate the seeding of these areas by bacteria. Tropical pyomyositis, pyogenic liver and renal abscesses are frequent diseases in tropical areas. The visceral larva migrans syndrome is caused by the presence, in the human body, of larvae of worms that have other animals as their definitive host, most commonly being caused by Toxocara canis. The larvae migrate to various body organs leading to many inflammatory reactions in the form of granuloma and tissue necrosis. In this review we discuss the possible host-parasite-bacteria interactions that would favour the formation of abscesses in the organs involved by the larva of T. canis and present preliminary results of a clinical and experimental study undertaken during the last four years to define the role of this parasite in the pathogenesis of the abscesses.

Schistosomiasis and associated infections

In hospital-based series viral hepatitis B has been frequently described in association with schistosomiasis whilst in field-based studies the association has not been confirmed. The association between schistosomiasis and Salmonella bacteraemia has been well documented. More recently, acute schistosomiasis has been shown to be a facilitating factor in the genesis of pyogenic liver abscesses caused by Staphylococcus aureus. New evidences indicate an interaction between the acquired immunodeficiency syndrome (AIDS) and schistosomiasis. In this paper, data on the association of schistosomiasis with other infections are updated.

Visceral larva migrans and tropical pyomyositis: a case report

We report a case of tropical pyomyositis in a boy who presented with a severe febrile illness associated with diffuse erythema, and swelling in many areas of the body which revealed on operation extensive necrotic areas of various muscles that required repeated débridement. The patient gave a history of contact with dogs, and an ELISA test for Toxocara canis was positive. He also presented eosinophilia and high serum IgE levels. Staphylococcus aureus was the sole bacteria isolated from the muscles affected. We suggest that tropical pyomyositis may be caused by the presence of migrating larvae of this or other parasites in the muscles. The immunologic and structural alterations caused by the larvae, in the presence of concomitant bacteremia, would favour seeding of the bacteria and the development of pyomyositis.

Acute schistosomiasis: report on five singular cases

The cases of five patients with unusual manifestations of acute schistosomiasis mansoni are described in this paper. One patient developed skin lesions, three displayed diverse lung involvement, and one presented pyogenic liver abscesses caused by Staphylococcus aureus.

[Schistosomiasis and viral hepatitides: a review]

The papers published on the association of schistosomiasis with viral hepatitis (B, C and D) are reviewed. The shortcomings of each work are pointed out and suggestions are forwarded to try and direct the investigations on this probable interaction.

[Pyogenic liver abscess and schistosomiasis mansoni in the state of Espírito Santo]

A possible association of the acute toxemic form of schistosomiasis and pyogenic liver abscess (PLA) has been recently suggested. As in the west of the Espírito Santo state schistosomiasis is endemic and PLA are frequently diagnosed in the Children's Hospital of Vitória we reviewed the records of the Hospital during the period from May 1991 to April 1993 to: a) identify all cases of PLA in which Schistosoma mansoni infection was present and b) annotate the procedence of each case to verify if there is an association of the two diseases. 65 cases of PLA were recorded and 39 had the result of a stool examination, being three positive for Schistosoma mansoni (7.6%) and 26 for other helminth (mainly Ascaris and Trichocephalus). The procedence of the patients showed that only 7 (10.7%) came from endemic areas. These results show that an association of Schistosoma mansoni infection and PLA was not significative in the country, where the acute toxemic form is not frequent. The great majority of PLA in this study came from the urban periphery of Vitória, where transmission of schistosomiasis does not occur but intestinal helminth infections are extremely frequent. The great majority of PLA in this study came from the urban periphery of Vitória, where transmission of schistosomiasis does not occur but intestinal helminth infections are extremely frequent. As 40% of these PLA were cryptogenetic it is possible that the immunomodulation induced by intestinal parasites and the liver granulomas produced by the larvae of these helminths would be predisposing factors for pyogenic liver abscess.

Pyogenic liver abscesses and acute schistosomiasis mansoni: report on 3 cases and experimental study

Three children with acute schistosomiasis mansoni developed pyogenic liver abscesses. The abscesses were diagnosed by ultrasonography and confirmed during laparotomy. Staphylococcus aureus were the sole bacteria isolated from the abscesses. An experimental study was carried out in mice to establish whether schistosomiasis is a predisposing cause for pyogenic liver abscesses. Seventeen mice (group 1) were infected with 40 Schistosoma mansoni cercariae (LE strain) and 60 d later inoculated intravenously with a strain of Staph. aureus, isolated from a patient with bacteraemia; 17 mice infected with Sch. mansoni (group 2), 19 infected with bacteria alone (group 3), and 18 uninfected mice (group 4), served as controls. Thirteen group 1 mice (77%) developed multiple liver abscesses while none was observed in the controls. These results indicate that acute schistosomiasis mansoni concurrent with Staph. aureus bacteraemia favours the colonization of the liver by bacteria and the development of pyogenic hepatic abscesses.

Schistosomiasis: predisposing cause for the formation of hepatic abscesses? Case report

An adult patient with chronic schistosomiasis from an endemic area, complained about a seven day fever, along with jaundice and lumbar backache on the right side. Image exams showed multiple pyogenic liver abscesses. All the classic etiologies were discarded through clinical, radiological and laboratorial criteria. Schistosomiasis can cause pylephlebitis as a complication, along with immunesuppression, granulomatous reaction with central lobular liver necrosis and a greater risk of infection. The authors suggest that schistosomiasis in its chronic form may be the predisposing cause of multiple pyogenic liver abscesses, especially in endemic areas.

[Fever of unknown origin: guidelines, clinical clues and complementary examinations]

Dez preceitos, vinte pistas clínicas e os exames complementares úteis na avaliação inicial dos pacientes com febre de origem indeterminada (FOI) são apresentados pelos autores.

Acute schistosomiasis: clinical, diagnostic and therapeutic features

Three distinct syndromes caused by schistosomiasis have been described: cercarial dermatitis or swimmer's itch, acute schistosomiasis or Katayama fever, and chronic schistosomiasis. Complications of acute schistosomiasis have also been reported. The absence of a serological marker for the acute stage has hindered early diagnosis and treatment. Recently, an ELISA test using KLH (keyhole limpet haemocyanin) as antigen, has proved useful in differentiating acute from chronic schistosomiasis mansoni. Clinical and experimental evidence indicate that steroids act synergistically with schistosomicides in the treatment of Katayama syndrome. In this paper, clinical, diagnostic and therapeutic features of acute schistosomiasis are updated.