Strongyloidiasis

Factors associated with the sexual transmission of Strongyloides stercoralis in men who have sex with men: A systematic review

Strongyloides stercoralis is a parasitic worm with a complex life cycle and can cause significant morbidity, including a proctocolitis and life-threatening hyperinfection syndrome. Limited reports from non-endemic areas, including in men who have sex with men (MSM), suggest sexual transmission of S. stercoralis. In this systematic review of the published literature, we aimed to explore the associated factors of S. stercoralis in MSM. We systematically searched three bibliographical databases (MEDLINE, CINAHL and EMBASE) up to November 2022. We used a two-stage process to assess eligibility: the primary author conducted an initial screen of abstracts, and then three authors conducted independent full manuscripts to determine the final eligible manuscripts. We only included manuscripts written in English that contained data on specific factors associated with sexual transmission in MSM. We used the STROBE checklist to assess the risk of bias and synthesized the narrative data using the SWiM method. Seven manuscripts were eligible for this review (four case reports, one case series, one cross-sectional study and one experimental study), which included 22 individuals from Europe and the Americas. From these studies, S. stercoralis in MSM was associated with living with HIV (including having a low CD4 count and not using antiretrovirals), having a concomitant sexually transmitted infection (Chlamydia trachomatis, Neisseria gonorrhoeae, Treponema pallidum and hepatitis C) and a concomitant (sexually transmitted) protozoal infection (Entamoeba histolytica, Giardia lamblia), travel to the S. stercoralis endemic area, multiple sexual partners from endemic areas, oro-anal sexual contact and chemsex. Although limited by the number of cases in the literature, we have highlighted some possible biological and behavioural risk factors associated with the sexual transmission of S. stercoralis in MSM that could be used to both target future research and S. stercoralis public health control interventions.

Hepatic pseudotumor associated with Strongyloides infection: A case report

BACKGROUND

Strongyloides sterocoralis is a parasitic infection caused by a roundworm that is transmitted through soil contaminated with larvae. It can infrequently cause hepatic abscesses in immunocompromised patients and is rarely reported to form hepatic lesions in immunocompetent hosts.

CASE SUMMARY

We present a case study of a 45-year-old female who presented with right upper quadrant abdominal pain and constitutional symptoms for several weeks. Cross-sectional imaging identified several malignant-appearing liver masses. Further investigation, including serological testing and histopathologic examination, revealed the presence of serum Strongyloides antibodies and hepatic granulomas with extensive necrosis. Following treatment with ivermectin for 2 wk, there was complete resolution of the liver lesions and associated symptoms.

CONCLUSION

This case highlights the importance of considering parasitic infections, such as Strongyloides, in the differential diagnosis of hepatic masses. Early recognition and appropriate treatment can lead to a favorable outcome and prevent unnecessary invasive procedures. Increased awareness among clinicians is crucial to ensure the timely diagnosis and management of such cases.

Canine gastrointestinal parasites perceptions, practices, and behaviours: A survey of dog owners in Australia

Many species of canine gastrointestinal (GI) parasites are known to be zoonotic meaning that dog owners' management and practices are key to preventing exposure of humans and dogs as well as contamination of the environment. As Australia has one of the highest rates of pet ownership in the world, we administered an online questionnaire to dog owners across the nation to assess their perceptions, practices, and behaviours towards canine GI parasites. Descriptive analysis was performed to summarise perceptions and management practices. Factors associated with the suitability of parasiticide treatments applied were investigated using uni- and multivariable ordinal regression. Just over a half of dog owners considered parasites as very or extremely important for their dog's health (59%) and less than a half as very or extremely important for human health (46%). Although the majority of dog owners stated that they deworm their dogs (90%), only the 28% followed best practice guidelines, i.e. administered a monthly prophylactic treatment all-year round. A large proportion of respondent dog owners administered prophylactic treatment at an inappropriate frequency (48%) or did not treat for canine GI parasites at all (24%). Attending vet visits at least once a year or once every six months and having a very comfortable or prosperous financial position were significantly associated with following best deworming prophylaxis guidelines. This study demonstrates that a proportion of dog owners in Australia is not complying with best practice regarding the control of canine GI parasites and is potentially exposing themselves and their dogs to the risk of infections. Veterinarians are called to implement dog owner's education, raise their awareness on the threats canine parasitic diseases pose to both dogs and humans and finally, encourage them to follow a monthly prophylactic treatment for canine GI parasites all year round.

Severe strongyloidiasis: a systematic review and meta-analysis of 339 cases

Strongyloidiasis is a parasitosis representing a significant public health problem in tropical countries. It is often asymptomatic in immunocompetent individuals but its mortality rate increases to approximately 87% in severe forms of the disease. We conducted a systematic review, including case reports and case series, of Strongyloides hyperinfection and dissemination from 1998 to 2020 searching PubMed, EBSCO and SciELO. Cases that met the inclusion criteria of the Preferred Reported Items for Systematic Reviews and Meta-Analyses (PRISMA) checklist were analysed. Statistical analysis was performed using Fisher's exact test and Student's t-test and a Bonferroni correction for all the significant values. A total of 339 cases were included in this review. The mortality rate was 44.83%. The presence of infectious complications, septic shock and a lack of treatment were risk factors for a fatal outcome. Eosinophilia and ivermectin treatment were associated with an improved outcome.

Polymicrobial bacteremia and Strongyloides hyperinfection syndrome: Vigilance in patients on corticosteroids

Strongyloidiasis is a worldwide parasitic infection. Many who develop infection remain asymptomatic. Due to Stronygloides autoinfection cycle it can result in chronic infection over decades. Immunosuppression particularly with corticosteroids has been associated with a rapid acceleration of the autoinfection cycle known as Strongyloides hyperinfection syndrome. The hyperinfection syndrome has severe complications and is associated with significant patient mortality. Here we report a case of hyperinfection complicated by polymicrobial bacteremia and intestinal ileus and review the literature regarding the hyperinfection syndrome.

Prevalence of Strongyloides stercoralis in the immunocompetent and immunocompromised individuals in Iran: a systematic review and meta-analysis

Strongyloidiasis is a neglected tropical disease mostly distributed in tropical and subtropical regions. The current study evaluated the prevalence of Strongyloides stercoralis in immunocompetent and immunodeficient patients in Iran. The available online literature published from June 1994 to October 2020 was obtained from multiple English databases (PubMed, Science Direct, Scopus, Web of Science and Google Scholar) and four Persian databases (Magiran, Iran Medex, Iran Doc and SID). All statistical analyses were performed using R software (version 3.6) meta-package and p-values <0.05 were considered significant. From 1051 articles, 74 studies (248 656 individuals) met the inclusion criteria. The pooled prevalence of S. stercoralis was 2% (95% confidence interval [CI] 1 to 3) and 4% (95% CI 1 to 8) in immunocompetent and immunodeficient patients, respectively. In immunodeficient cases, the pooled prevalence of studies utilizing serology, culture and microscopic methods was 10% (95% CI 2 to 23), 1% (95% CI 0 to 6) and 1% (95% CI 0 to 1), respectively. In immunocompetent cases, the pooled prevalence of studies utilizing microscopic, culture and molecular methods was 2% (95% CI 1 to 3), 2% (95% CI 1 to 4) and 2% (95% CI 0 to 6), respectively. We propose an appropriate screening and control program along with comprehensive research regarding the frequency of strongyloidiasis in the country.

A Case of Ulcerated Gastric Mass and Anemia due to Strongyloidiasis

Strongyloidiasis is an intestinal infection caused by the nematode Strongyloides, and it is rarely seen in our clinical practice in the United States. Although it remains localized to the gastrointestinal tract most of the time, it can disseminate to other organs when it causes autoinfection in the setting of immunosuppression. The clinical manifestations vary depending on the involved organ. A case of disseminated strongyloidiasis presenting as a case of ulcerated gastric mass and anemia is described here along with a review of the literature on this condition.

Infectious Lung Disease

Infectious diseases are one of the main causes of morbidity and mortality worldwide. With new pathogens continuously emerging, known infectious diseases reemerging, increasing microbial resistance to antimicrobial agents, global environmental change, ease of world travel, and an increasing immunosuppressed population, recognition of infectious diseases plays an ever-important role in surgical pathology. This becomes particularly significant in cases where infectious disease is not suspected clinically and the initial diagnostic workup fails to include samples for culture. As such, it is not uncommon that a lung biopsy becomes the only material available in the diagnostic process of an infectious disease. Once the infectious nature of the pathological process is established, careful search for the causative agent is advised. This can often be achieved by examination of the hematoxylin and eosin-stained sections alone as many organisms or their cytopathic effects are visible on routine staining. However, ancillary studies such as histochemical stains, immunohistochemistry, in situ hybridization, or molecular techniques may be needed to identify the organism in tissue sections or for further characterization, such as speciation.

Strongyloidiasis in Ethiopia: systematic review on risk factors, diagnosis, prevalence and clinical outcomes

Background

Strongyloidiasis is a gastrointestinal infection caused by the parasitic nematode Strongyloides stercoralis. It is estimated to infect up to 370 million people globally and is predominately found in tropical and subtropical areas of socioeconomic disadvantage.

Main body

This systematic literature review identified studies published in the last ten years on the risk factors, diagnosis, prevalence and/or clinical outcomes of strongyloidiasis in Ethiopia. The prevalence of S. stercoralis ranged from 0.2 to 11.1% in adults, 0.3% to 20.7% in children, 1.5% to 17.3% in HIV positive adults and 5% in HIV positive children. The identified studies primarily used microscopy based techniques that potentially underestimated the prevalence four fold compared with serology and PCR. Strongyloidiasis in children presents a particularly significant issue in Ethiopia as children often presented with anemia, which is associated with impaired mental and cognitive development. The most significant risk factor for strongyloidiasis was HIV status and although other risk factors were identified for helminth infections, none were statistically significant for S. stercoralis specifically. Several studies detected S. stercoralis in dogs and non-biting cyclorrhaphan flies. However, future research is needed to explore the role of these reservoirs in disease transmission.

Conclusions

This review demonstrated that strongyloidiasis is an overlooked and neglected disease in Ethiopia. There is a need for a systematic approach using a combination of molecular and serology based diagnostic methods to ascertain the true incidence and burden of strongyloidiasis in Ethiopia. Further research is also needed to break the cycle of transmission by identifying environmental reservoirs, risk factors and exploring the potential for zoonotic transfer.

Electronic supplementary material

The online version of this article (10.1186/s40249-019-0555-3) contains supplementary material, which is available to authorized users.

Strongyloides stercoralis larvae in the urine of a patient with transitional cell carcinoma of the bladder: a case report

Disseminated infection with Strongyloides stercoralis refers to the massive migration of infective larvae from the gastrointestinal tract to other organs that are not involved in the normal life cycle of the parasite. We describe the case of a Nigerian male with transitional cell carcinoma of the bladder in whom larvae of S. stercoralis was identified in the urine. This report involves a 60-year old male Nigerian presenting to the Urology clinic of the Jos University teaching hospital, Nigeria with disseminated S. stercoralis. The index patient presented with a 5 month history of total haematuria, urinary frequency, urgency, nocturia, straining to pass urine, feeling of incomplete voiding and terminal dribbling. He also had episodes of suprapubic pain. Physical examination revealed a cachexic patient who had mild suprapubic tenderness. Urinary examination showed numerous red blood cells and rhabditiform larvae of S. stercoralis. Abdominal ultrasound revealed a heterogeneous mass in the urinary bladder measuring 4.0 × 3.3 cm. Abdominal computed tomography also showed an irregular mass measuring 4.2 × 3.8 cm with HU of 41 projecting into the bladder from the posterior wall towards the dome. Histology of the biopsy specimen revealed transitional cell carcinoma. The patient was treated with a single dose of oral ivermectin but died 1 week later. Physicians working in areas that are endemic for S. stercoralis should consider investigating immunocompromised patients for S. stercoralis infection given the poor prognosis of disseminated infection in this group of patients.

Prevalence of Opportunistic Intestinal Parasites and Associated Factors among HIV Patients while Receiving ART at Arba Minch Hospital in Southern Ethiopia: A Cross-sectional Study

BACKGROUND

Opportunistic Intestinal Parasites (OIPs) commonly cause morbidity in HIV/AIDS patients due to the decline of CD4+T-cells. The burden of Opportunistic Intestinal Parasitic Infections (OIPIs) in Ethiopia is expected to be high due to poor sanitation and co-pandemicity of HIV/AIDs. Therefore, frequent assessment of the magnitude and associated factors for intestinal parasitosis is essential for the management of HIV/AIDS patients.

METHODS

A hospital based cross-sectional study was conducted among patients attending Arba Minch Hospital Antiretroviral Therapy (ART) Clinic from March to June 2016. Stool specimens were processed for parasitological examination using direct wet mount, formol-ether sedimentation and modified Ziehl-Neelsen staining techniques. CD4+ T-cell count data were taken from patients' medical records. A structured questionnaire was used to collect data on socio-demographic characteristics and possible associated factors for OIPIs. All the data were analyzed using SPSS version 20.

RESULTS

Two hundred and twenty ART patients participated in the study. The overall prevalence of intestinal parasitic infections was 28.18% while that of OIPIs alone was 17.72%. Among identified intestinal parasites, Cryptosporidium species accounts for the highest frequency (19/220, 8.63%), followed by Cyclospora species (13/220, 5.90%). Presence of domestic animals (AOR=2.07, 95%CI:1.07-8.40, P= 0.032) and CD4+ T-cell count <500cell/µl (AOR=4.66, 95%CI:1.17-5.35, P= 0.001) were significantly associated with OIPIs.

CONCLUSION

The study indicated that co-infection rate of OIPs is high among ART patients. It also found that contact with domestic animals and having CD4+ count <500 cell/µl predict for the presence of OIPs.

Anemia, intractable vomiting, chronic diarrhea, and syndrome of inappropriate antidiuretic secretion: a diagnostic dilemma: Disseminated strongyloidosis in a patient with newly diagnosed HTLV infection-case report and review of literature

RATIONALE

Strongyloidiasis hyperinfection and disseminated disease have high mortality rates due to several complications and early detection of Strongyloides infection is therefore prudent.

PATIENT CONCERNS

A 37-year-old male patient came with chronic diarrhea, intractable vomiting and was found to have hyponatremia, and anemia on the initial laboratory tests.

DIAGNOSES

Further work up revealed syndrome of inappropriate antidiuretic secretion to be the cause of the hyponatremia in addition to gastrointestinal loses. His hospital course was complicated by persistent hyponatremia and later development of partial small bowel obstruction.

INTERVENTIONS

Considering his symptoms we had a suspicion of small bowel pathology for which he underwent an esophagogastroduodenoscopywith biopsies that revealed strongyloidosis as the cause of his symptoms. He was also found to have human T-cell lymphotropic virus infection, likely contributing to the disseminated disease.

OUTCOMES

He was started on ivermectin with complete resolution of symptoms and improvement of hyponatremia.

LESSONS

It is very important to suspect Strongyloides infection in a patient presenting with syndrome ofinappropriate antidiuretic secretion as hyperinfection and disseminated disease can be life threatening without antihelmintic therapy.

Strongyloides Hyperinfection Syndrome Combined with Cytomegalovirus Infection

The mortality in Strongyloides hyperinfection syndrome (SHS) is alarmingly high. This is particularly common in bone marrow, renal, and other solid organ transplant (SOT) patients, where figures may reach up to 50–85%. Immunosuppressives, principally corticosteroids, are the primary triggering factor. In general, the clinical features of Strongyloides stercoralis hyperinfection are nonspecific; therefore, a high index of suspicion is required for early diagnosis and starting appropriate therapy. Although recurrent Gram-negative sepsis and meningitis have been previously reported, the combination of both cytomegalovirus (CMV) and strongyloidiasis had rarely been associated. We here describe a patient who survived SHS with recurrent Escherichia coli (E. coli) urosepsis and CMV infection.

Strongyloidiasis in the immunocompetent: an overlooked infection

Strongyloidiasis is a parasitic infestation caused by Strongyloides stercoralis. Most cases are asymptomatic; however, symptomatic patients may present with a wide range of non-specific cutaneous, pulmonary, or gastrointestinal symptoms posing a diagnostic dilemma and delay in diagnosis. We report a case of a 58-year-old female who presented with months of generalized pruritus and abdominal discomfort along with persistent eosinophilia due to strongyloidiasis, which completely resolved with treatment.

Cutaneous Strongyloides Infection Postchemotherapy

BACKGROUND AND OBJECTIVE

While clinical symptoms of strongyloidiasis are often nonspecific, larva currens (with erythematous, serpiginous, and pruritic papules and plaques) should prompt investigation including stool microscopy, serology, and skin biopsy of the lesion. Appropriate diagnosis and treatment with ivermectin is necessary, especially in the immunocompromised patient who is at increased risk for hyperinfection syndrome and disseminated disease.

CONCLUSION

We present a 61-year-old immunocompromised man with presentation of larva currens of cutaneous strongyloides infection without symptoms of hyperinfection or disseminated disease.

Co-infection with Nocardia asteroides complex and Strongyloides stercoralis in a patient with autoimmune hemolytic anemia

We describe an unusual case of pulmonary nocardiosis co-existing with Strongyloides stercoralis hyperinfection syndrome in a patient with autoimmune hemolytic anemia who was being treated with corticosteroids. This case highlights the importance of being aware of the possibility that infections can co-exist in immunosuppressed patients. To the best of our knowledge, this is the first report of co-infection with Nocardia asteroides and S. stercoralis.

Strongyloides stercoralis: Global Distribution and Risk Factors

BACKGROUND

The soil-transmitted threadworm, Strongyloides stercoralis, is one of the most neglected among the so-called neglected tropical diseases (NTDs). We reviewed studies of the last 20 years on S. stercoralis's global prevalence in general populations and risk groups.

METHODS/PRINCIPAL FINDINGS

A literature search was performed in PubMed for articles published between January 1989 and October 2011. Articles presenting information on infection prevalence were included. A Bayesian meta-analysis was carried out to obtain country-specific prevalence estimates and to compare disease odds ratios in different risk groups taking into account the sensitivities of the diagnostic methods applied. A total of 354 studies from 78 countries were included for the prevalence calculations, 194 (62.4%) were community-based studies, 121 (34.2%) were hospital-based studies and 39 (11.0%) were studies on refugees and immigrants. World maps with country data are provided. In numerous African, Asian and South-American resource-poor countries, information on S. stercoralis is lacking. The meta-analysis showed an association between HIV-infection/alcoholism and S. stercoralis infection (OR: 2.17 BCI: 1.18-4.01; OR: 6.69; BCI: 1.47-33.8), respectively.

CONCLUSIONS

Our findings show high infection prevalence rates in the general population in selected countries and geographical regions. S. stercoralis infection is prominent in several risk groups. Adequate information on the prevalence is still lacking from many countries. However, current information underscore that S. stercoralis must not be neglected. Further assessments in socio-economic and ecological settings are needed and integration into global helminth control is warranted.

Hyperinfection with Strongyloides stercoralis

Strongyloidiasis is caused by Strongyloides stercoralis, which commonly produces gastrointestinal problems. If immune systems are compromised, the nematode larvae may spread and produce Strongyloides hyperinfection. Diagnosis of strongyloidiasis is based on the observation of larvae in coproparasitological studies. We present a case of a 49-year-oldman, VIH, who developed Strongyloides hyperinfection, diagnosed postmortem. Our patient reached the dissemination stage, which resulted in severe damage to the stomach and intestine, perforation of the intestinal wall, as well as sepsis due to the dissemination of bacteria. The diagnosis is difficult because of the low larvae excretion in stools. It is usually performed by the microscopic examination of fresh and fixed enriched stool samples. Serology was reported to be useful for screening and follow-up after treatment. This case reaffirms that HIV immunosuppression favours the dissemination of S stercoralis larvae. Thus, a search for intestinal parasites should be considered in similar cases.

Diarrhea in the immunocompromised patient

Diarrhea is a common problem in patients with immunocompromising conditions. The etiologic spectrum differs from patients with diarrhea who have a normal immune system. This article reviews the most important causes of diarrhea in immunocompromised patients, ranging from infectious causes to noninfectious causes of diarrhea in the setting of HIV infection as a model for other conditions of immunosuppression. It also deals with diarrhea in specific situations, eg, after hematopoietic stem cell or solid organ transplantation, diarrhea induced by immunosuppressive drugs, and diarrhea in congenital immunodeficiency syndromes.

Opportunistic and other intestinal parasites among HIV/AIDS patients attending Gambi higher clinic in Bahir Dar city, North West Ethiopia

OBJECTIVE

To determine the magnitude of opportunistic and non-opportunistic intestinal parasitic infections among HIV/AIDS patients in Bahir Dar.

METHODS

Cross-sectional study was conducted among HIV/AIDS patients attending Gambi higher clinic from April1-May 30, 2009. Convenient sampling technique was employed to identify the study subjects and hence a total of 248 subjects were included. A pre-tested structured questionnaire was used to collect socio-demographic data of patients. Stool samples were examined by direct saline, iodine wet mount, formol-ether sedimentation concentration and modified Ziehl-Neelsen staining technique.

RESULTS

Out of 248 enrolled in the study, 171(69.0%) (90 males and 81 females) were infected with one or more intestinal parasites. The highest rate of intestinal parasites were observed among HIV/AIDS patients (80.3%, 151/188), and the infection rate of HIV negative individuals was 33.3% (20/60). Cryptosporidum parvum (43.6%), Isospora belli (15.5%) and Blastocystis hominis (10.5%) were opportunistic parasites that were found only in HIV/AIDS patients.

CONCLUSIONS

Opportunistic parasite infections are common health problem among HIV/AIDS patients in the study area. Therefore, early detection and treatment of these parasites are important to improve the quality of life of HIV/AIDS patients.

Duodenal obstruction - an unusual presentation of Strongyloides stercoralis enteritis: a case report

Background

Intestinal obstruction is a poorly recognized and probably underreported complication of strongyloidiasis. We present herein an unusual case, of complete duodenal obstruction caused by S. stercoralis.

Methods

A systematic review of the literature examining the clinical course, diagnostic methods, and outcome of this rare complication of strongyloidiasis was performed.

Results

A 42-year-old woman presented with a 5-month history of abdominal pain, vomit, and weight loss. An abdominal CT scan showed an obstruction of the third part of the duodenum. Segmental intestinal resection was carried out and histopathology examination revealed heavy Strongyloides stercoralis infestation. Duodenal obstruction is a rare complication of S. stercoralis infection, with only 8 cases described in the literature since 1970. Most of the patients are males, middle-aged, and the diagnosis was made by duodenal aspirate/biopsy, or analysis of surgical specimen.

Conclusions

Duodenal obstruction is an unusual, but potential fatal, complication of S. stercoralis infection. The large spectrum of clinical manifestation and lack of classic clinical syndrome make the final diagnosis of strongyloidiasis extremely difficult. A high index of suspicion, mainly in patients from endemic areas, is needed for correct and early diagnosis of this uncommon presentation of Strogyloides stercoralis enteritis.

Strongyloides stercoralis and the immune response

The immune system is a highly evolved network of cells and molecules that can distinguish between invading pathogens and the body's own cells. But helminths, in their complex forms, are capable of down-regulating host immunity, protecting them from being eliminated and also minimizing severe pathology in the host. This review focuses on Strongyloides stercoralis and the immune responses in immunocompetent and/or immunocompromised individuals. It also highlights the implications for diagnosis/treatment and draws attention to an emerging public health disease. The solution to reducing the prevalence of strongyloidiasis remains on the effectiveness of pre-emptive measures in endemic communities, increased awareness, prompt early diagnosis as well as timely treatment.

Strongyloidiasis in transplant patients

Strongyloides stercoralis is an intestinal nematode that can persist in the human host for decades after the initial infection and can progress to fulminant hyperinfection syndrome in immunocompromised hosts. We describe a patient who died of Strongyloides hyperinfection syndrome 2 months after orthotopic heart transplantation and discuss approaches to prevention, diagnosis, and treatment. Current practice guidelines recommend screening for and treatment of Strongyloides infection before transplantation, but physicians in the United States often miss opportunities to identify patients with chronic strongyloidiasis. Screening tests have limitations, and clinical suspicion remains an important component of the evaluation before transplantation. After immunocompromised patients develop hyperinfection syndrome, diagnosis is often delayed and mortality is high, so emphasis must be placed on screening and treatment before transplantation. We review current strategies for prevention, diagnosis, and treatment of chronic intestinal strongyloidiasis in patients who will undergo transplantation and discuss the clinical features and management of Strongyloides hyperinfection syndrome in transplant recipients.

Sexual transmission of intestinal parasites in men who have sex with men

Direct oral-anal sexual contact is a common practice among men who have sex with men (MSM) and is implicated in the transmission of various enteric pathogens including intestinal parasites. The present study reviewed data on the sexual transmission of intestinal parasites among MSM, and highlighted advances in the diagnosis of such infections. The emergence and spread of intestinal parasites is of public health concern particularly in the homosexual community. Intestinal parasitic infection should be considered in the differential diagnosis of gastrointestinal disease in this population. Combination of traditional diagnostic procedures with implementation of testing based on novel molecular methods in the accurate identification of intestinal parasites is important so that early intervention and control of infection is facilitated.

Strongyloides stercoralis hyperinfection syndrome after liver transplantation: case report and literature review

Strongyloides stercoralis is an intestinal nematode that causes human infections and whose life cycle has special features, including autoinfection. Strongyloides infection may be asymptomatic for years, owing to a low parasite load. During immunosuppressive therapy, however, if cellular immunity is depressed, autoinfection can occur at a higher rate, resulting in hyperinfection syndrome. In this specific circumstance, it can become a fatal illness. We describe a case of hyperinfection syndrome in a liver transplant recipient and also review the literature.

Fatal relapse of disseminated strongyloidiasis in an HIV-positive patient, despite ivermectin treatment

There are no established guidelines for the treatment of disseminated strongyloidiasis in immunosuppressed patients, and many different treatment regimens have been used. Here, the case of a 48-year-old, HIV-positive, Congolese man, who was hospitalized for disseminated tuberculosis but developed life-threatening disseminated strongyloidiasis, is described. This patient died, with relapsing disseminated strongyloidiasis, 3 months after being treated with ivermectin. The reasons for this poor outcome and the various treatment options for strongyloidiasis in HIV-infected patients are discussed.

Eosinophilia during intestinal infection

Eosinophilia is a common finding in tropical developing countries, and is mainly caused by chronic helminth infections, predominantly of the gut. Although only a minority of infections is symptomatic, development during childhood can be impaired, and in some patients serious complications and sequelae may occur. Eosinophilia in helminth infection is typically associated with a strong Th2 immune response, and eosinophils can effectively kill or damage larvae and adult worms in vitro. However, in vivo, eosinophils are only partly effective in the control of helminth infection, and recent research has shown that eosinophils are involved in a range of immunomodulatory effects, such as increased production of the down-modulatory cytokines interleukin 10 and tumour growth factor beta, as well as stimulation of regulatory T cells and alternatively activated macrophages. Increasing evidence suggests that immunomodulation favours parasite survival and reduces immune pathology. On the other hand, immunomodulation induced by helminth infections may contribute to protection from allergic and autoimmune responses, as proposed by the 'hygiene hypothesis' to explain the increase in allergic diseases in the industrialised world. The predictive value of eosinophilia for the presence of helminth infections is limited and depends on the epidemiological background and the extent of the eosinophilia. It increases considerably in populations with a high prevalence of parasitic infections, as in developing tropical countries or in travellers to those areas.

Strongyloides hyperinfection syndrome after intestinal transplantation

Strongyloides stercoralis is a helminth with the ability to autoinfect the human host and persist asymptomatically for several years. Immunosuppression can accelerate autoinfection and result in Strongyloides hyperinfection syndrome (SHS), which is associated with significant morbidity and mortality. Immunosuppressed solid organ transplant recipients, particularly in the setting of rejection, are at increased risk for reactivation of latent infections, such as Strongyloides. We describe a case of SHS in an intestinal transplant recipient; we hypothesize that she acquired the infection from the donor. We also review the current literature and address both prophylaxis and treatment of strongyloidiasis in the solid organ transplant patient.

[Parasites as a cause of urticaria. Helminths and protozoa as triggers of hives?]

Urticaria is one of the most prevalent disorders in dermatological practice. The disease can be incapacitating. There are clear pathophysiological and epidemiological hints that helminths and protozoa are rare but treatable causes of acute and chronic urticaria. Doctors and patients are often not aware that parasitic diseases are increasingly common even in industrialized countries due to a steep rise in migration and international travel. This review presents the most important parasitic causes of urticaria and provides relevant details regarding personal history, clinical presentation, diagnosis and therapy.

Unsuspected strongyloidiasis in hospitalised elderly patients with and without eosinophilia

The prevalence and associated factors of chronic uncomplicated strongyloidiasis were estimated among 200 consecutive elderly patients (aged >or= 60 years) admitted to a general hospital in northern Italy. One-hundred patients had a peripheral eosinophil concentration >or= 500 cells/microL (group A), and 100 were age- and gender-matched controls (group B). Measurements included serum IgG anti-Strongyloides antibody titre by an indirect immunofluorescence assay, combined with faecal culture for Strongyloides stercoralis. Anti-Strongyloides antibodies were detected in 28 patients (at high titre in 11 patients). Seropositivity was significantly more common among group A than among group B patients (OR 4.85). Strong seropositivity for anti-Strongyloides antibodies was associated with farm work (p < 0.001), but not with other patient characteristics or with signs and symptoms of strongyloidiasis. In conclusion, strongyloidiasis was relatively common among elderly in-patients; eosinophilia and a history of farm work were the most useful indications for this diagnosis.

Síndrome de malabsorción intestinal producido por Strongyloides stercoralis asociado con el síndrome de Loeffler en una mujer de 29 años de edad

We report a case of chronic infection by Strongyloides stercoralis in a 29-year-old Colombian woman who had been living in Spain for 2 years. The patient had recurrent abdominal pain and malabsorption syndrome. The diagnosis was made through intestinal biopsy in upper gastrointestinal endoscopy. Transport of the parasite through the lung parenchyma (Loeffler syndrome) was visible on simple chest X-ray. Bronchoalveolar lavage, bronchoalveolar aspirate and repeated stool examination were negative.

Efficacy and safety of ivermectin and thiabendazole in the treatment of strongyloidiasis

Treatment of strongyloidiasis has been traditionally based on thiabendazole, despite its frequent gastrointestinal side effects and failure to achieve eradication of the parasite from faeces in approximately 30% of cases. Ivermectin has been shown to be more effective for treating chronic uncomplicated strongyloidiasis. The efficacy and tolerability of these drugs in a series of patients treated from 1999 to 2002 at the Oliva Health Centre, Valencia, Spain, are reported. A total of 88 patients diagnosed of strongyloidiasis were treated using the following regimens: thiabendazole 25 mg/kg/12 h for 3 consecutive days in 31 patients; ivermectin 200 mug/kg as a single dose in 22 patients; and ivermectin 200 mug/kg for 2 consecutive days in 35 patients. The efficacy and side effects were recorded. A total of 65 patients were male, and 23 female. The mean age was 64 +/- 12 years. Of the patients, 44 had worked barefoot in rice fields. Among the 31 patients treated with thiabendazole, 25 (78%) met the criteria for cure (the absence of parasite in faeces after examination of three samples collected on alternate days), and 5 (16%) experienced side effects (asthenia, epigastralgia and disorientation). Of the 22 patients treated with ivermectin on a single day, 17 (77%) met the criteria for cure, and 2 (9%) reported side effects (dizziness, dyspepsia). Among the 35 patients treated with ivermectin on 2 consecutive days, 100% met the criteria for cure, and 0% experienced side effects. In chronic uncomplicated strongyloidiasis, a treatment regimen consisting of ivermectin 200 mug/kg for 2 consecutive days provided the best results with regard to efficacy and tolerability. When the eosinophilia continued after treatment, we observed a high percentage of not-cure rate (7 of 9 patients, 77%).

Parasite-specific IgG response and peripheral blood eosinophil count following albendazole treatment for presumed chronic strongyloidiasis

BACKGROUND

In developed countries, asymptomatic chronic Strongyloides stercoralis infection occurs in immigrants from endemic regions of the world. Accurate and reliable means of diagnosis and follow-up are required for effective management. The role of S stercoralis enzyme-linked immunosorbent assay (ELISA) in this context was examined.

METHODS

In this study, 95 asymptomatic Laotian immigrants living in Melbourne, Australia, for an average of 12 years, were screened for S stercoralis infection using stool microscopy, eosinophil count, and serology by ELISA. Twenty-two patients with a positive ELISA were treated with albendazole, 400 mg twice daily for 3 days, and monitored with serology, fecal microscopy, and eosinophil counts at 2, 6, 12, and 36 months after treatment.

RESULTS

Patients with moderately reactive baseline ELISA and no eosinophilia had no significant change in either measure over the 36 months of follow-up. All patients with a strongly reactive baseline ELISA showed a reduction in reactivity over the first 6 months of treatment. However, in 50% of these patients, reactivity increased between 12 and 36 months, suggesting treatment failure and relapse of infection. One patient had confirmed treatment failure based on the development of hyperinfection syndrome.

CONCLUSION

The results support evidence that serology is a valuable tool in monitoring treatment responses in patients with suspected strongyloidiasis and highlights the need to ensure that S stercoralis is completely eradicated after treatment.

Life-threatening stings, bites, infestations, and parasitic diseases

Bites, stings and infestations can be fatal. Anaphylaxis to vespids and bees can be prevented with immunotherapy. Patients should be referred to an allergist. The acute care and prevention of arthropod injury is discussed below.

Intestinal strongyloidiasis: recognition, management, and determinants of outcome

Significant advances have occurred in our understanding of the biology, immunology, and immunopathology of the usually asymptomatic human infection by the intestinal parasite, Strongyloides stercoralis. Factors that increase the risk for the occurrence of symptomatic intestinal hyperinfection and/or often-fatal disseminated strongyloidiasis have been better defined. The pathophysiology underlying these risk factors, whether disease-related or iatrogenically induced, is a compromised immune system leading to dysfunction of TH-2 helper cells. These specialized lymphocytes are central to maintaining the delicate balance that exists between the infected human host and the stabilized parasite. Recognition of risk factors that impair the function of TH-2 lymphocytes is essential to heightening the index of clinical suspicion enhancing earlier, accurate diagnosis, and the introduction of appropriate therapy. This review summarizes what is understood about infection by S. stercoralis; its focus will be on the epidemiology, diagnosis, clinical presentation patterns in the immunocompetent and immunocompromised human hosts, and recommended treatment regimens.

Gelatin particle indirect agglutination and enzyme-linked immunosorbent assay for diagnosis of strongyloidiasis using Strongyloides venezuelensis antigen

Routine microscopical examination of stool specimens for diagnosis of strongyloidiasis is insensitive and serological methods using Strongyloides stercoralis antigen are at present not available for field studies. We evaluated 2 techniques, enzyme-linked immunosorbent assay (ELISA) and gelatin particle indirect agglutination (GPIA), using an antigen obtained from the rodent parasite, S. venezuelensis. Fifty-four Peruvian patients with different clinical forms of strongyloidiasis were studied: 12 asymptomatic, 31 symptomatic, and 11 hyperinfection cases. Our results demonstrate that both ELISA and GPIA using S. venezuelensis antigen are useful for diagnosis of strongyloidiasis, with sensitivities of 74.1% and 98.2%, respectively and a specificity of 100% for both techniques. We found that GPIA is a highly sensitive test for patients with suspected chronic infection and/or hyperinfection. In the hyperinfection cases, significantly lower concentrations of specific immunoglobulin antibodies and eosinophils (P < 0.001) were found compared with the asymptomatic and symptomatic cases.

Successful ivermectin treatment of hepatic strongyloidiasis presenting with severe eosinophilia

A 49-year-old, previously healthy nurse presented with hepatic lesions and severe peripheral eosinophilia due to strongyloidiasis. Imaging studies of the abdomen showed predominantly peripheral, confluent hepatic lesions. The hepatic lesions and eosinophilia did not show any improvement with albendazole, but completely resolved with ivermectin treatment. Our findings suggest that Strongyloides stercoralis can present with isolated focal hepatic lesions and severe eosinophilia, and resolves with ivermectin treatment.