Transjugular intrahepatic portosystemic shunt followed by splenectomy for complicated hepatosplenic schistosomiasis: a case report and review of the literature.

Hepatosplenic schistosomiasis is a complex clinical condition caused by the complications of chronic infection with Schistosoma species that cause intestinal schistosomiasis. Hepatosplenic schistosomiasis derives from the fibrotic reaction stimulated around parasite eggs that are transported by the mesenteric circulation to the liver, causing periportal fibrosis. Portal hypertension and variceal gastrointestinal bleeding are major complications of hepatosplenic schistosomiasis. The clinical management of hepatosplenic schistosomiasis is not standardised and a parameter that could guide clinical decision making has not yet been identified. Transjugular intrahepatic portosystemic shunt (TIPS) appears promising for use in hepatosplenic schistosomiasis but is still reported in very few patients. In this Grand Round, we report one patient with hepatosplenic schistosomiasis treated with TIPS, which resulted in regression of oesophageal varices but had to be followed by splenectomy due to persisting severe splenomegaly and thrombocytopenia. We summarise the main challenges in the clinical management of this patient with hepatosplenic schistosomiasis, highlight results of a scoping review of the literature, and evaluate the use of of TIPS in patients with early hepatosplenic schistosomiasis, to improve the prognosis.

Prospective cohort study using ultrasonography of Schistosoma haematobium-infected migrants.

BACKGROUND: Chronic infection with Schistosoma haematobium may lead to serious complications, including bladder carcinoma. Although it is recommended that only bladder masses not regressing within 6 months after praziquantel intake should be investigated invasively, cystoendoscopy is still often performed at diagnosis even in the absence of further signs of concern. No prospective study so far evaluated the evolution of bladder lesions after treatment in case of no risk of reinfection, which could inform case management. METHODS: Adult African migrants with active S. haematobium infection, as assessed by positive urine PCR or microscopy for eggs in urine or bladder biopsy, underwent urinary tract ultrasound at enrolment and at 1, 3, 6, 12 and 24 months after praziquantel treatment. Patients in advanced pregnancy or with known Schistosoma-unrelated chronic pathology of the urinary tract were excluded. RESULTS: Twenty-one patients, aged 18-29 years, participated in the study; ten (47.6%) had bladder masses on ultrasound. Follow-up ≥6 months was completed by 16 (76.2%) patients; ≥12 months by 14 (66.7%) and 24 months by 11 (52.4%). All patients with bladder lesions on enrolment completed a follow-up of ≥6 months. Lesions resolved completely by 6 months in all cases and no new development/re-appearance was observed. CONCLUSIONS: This is the first prospective, long-term follow-up study with ultrasound of patients with urinary schistosomiasis outside endemic areas. Mucosal masses in young patients regressed after treatment without recurrence, supporting the recommendation that invasive procedures should be avoided unless lesions or other symptoms/signs of concern persist for > 6 months. Further studies should assess the evolution of bladder lesions after treatment in larger populations, including older age groups, and, ideally, with parallel assessment of other biomarkers of urinary pathology and of residual S. haematobium active infection.

Large multicystic spinal lesion in a young African migrant: a problem of differential diagnosis.

We describe a rare case of large, fully cystic spinal schwannoma in a young adult from The Gambia. The initial clinical suspicion was spinal cystic echinococcosis. He came to our attention reporting progressive walking impairment and neurological symptoms in the lower limbs. An expansive lesion extending from L2 to S1 was shown by imaging (ie, CT scan and MRI). Differential diagnoses included aneurysmal bone cyst and spinal tuberculosis and abscess; the initial suggested diagnosis of spinal cystic echinococcosis was discarded based on contrast enhancement results. The final diagnosis of cystic schwannoma was obtained by histopathology of the excised mass. Cystic spinal lesions are rare and their differential diagnosis is challenging. Awareness of autochthonous and tropical infectious diseases is important, especially in countries experiencing consistent migration flow; however, it must be kept in mind that migrants may also present with 'non-tropical' pathologies.

Leprosy in Refugees and Migrants in Italy and a Literature Review of Cases Reported in Europe between 2009 and 2018.

Leprosy is a chronic neglected infectious disease that affects over 200,000 people each year and causes disabilities in more than four million people in Asia, Africa, and Latin America. The disease can appear with a wide spectrum of clinical forms, and therefore the clinical suspicion is often difficult. Refugees and migrants from endemic countries affected by leprosy can remain undiagnosed in Europe due to the unpreparedness of clinicians. We retrospectively describe the characteristics of 55 refugees/migrants with a diagnosis of leprosy established in Italy from 2009 to 2018. Continents of origin were Africa (42%), Asia (40%), and South and Central America (18%). The symptoms reported were skin lesions (91%), neuropathy (71%), edema (7%), eye involvement (6%), fever (6%), arthritis (4%), and lymphadenopathy (4%). Seven patients (13%) had irreversible complications. Overall, 35% were relapses and 66% multibacillary leprosy. Furthermore, we conducted a review of 17 case reports or case series and five nationwide reports, published in the same decade, describing 280 migrant patients with leprosy in Europe. In Europe, leprosy is a rare chronic infectious disease, but it has not completely disappeared. Diagnosis and treatment of leprosy in refugees and migrants from endemic countries are a challenge. European guidelines for this neglected disease in this high-risk population would be beneficial.

Ultrasound and intestinal lesions in Schistosoma mansoni infection: A case-control pilot study outside endemic areas.

BACKGROUND: Infection with Schistosoma mansoni is a major cause of morbidity and mortality in endemic areas, and is increasingly diagnosed in migrants and travellers outside transmission areas. Markers for the assessment of morbidity and impact of control programs in endemic areas and for the clinical management of patients in the clinical setting are scant, especially for intestinal involvement. Ultrasonography is well established to evaluate hepatosplenic pathology; on the contrary, ultrasound evaluation of intestinal schistosomiasis is virtually unexplored. In this pilot study, we aimed to describe and evaluate the accuracy of unenhanced intestinal ultrasound for morbidity due to intestinal S. mansoni infection. METHODOLOGY/PRINCIPAL FINDINGS: We performed a blind case-control study of unenhanced intestinal ultrasound on 107 adults accessing the outpatient clinic of our Centre for Tropical Diseases between January-July 2018 as part of a screening for tropical diseases in migrants and travellers returning from endemic areas. Other clinical and laboratory data were obtained routine examination reports. We could not find any overtly pathological thickness of the gut wall in the sigma, proximal ascending colon, and terminal ileum, in patients with S. mansoni infection (n = 17), S. haematobium infection (n = 7), positive anti-Schistosoma serology (n = 31), and uninfected individuals (n = 52), with no difference among groups as assessed by ANOVA. No polyps or other intestinal abnormalities were visualized. There was no significant change in gut wall thickness one month after treatment with praziquantel in patients with S. mansoni infection (n = 11). CONCLUSIONS/SIGNIFICANCE: Our preliminary results suggest that intestinal ultrasound might not be a sensitive tool for detecting minor intestinal morbidity due to schistosomiasis. Further studies in a hospital setting comparing colonoscopy and ultrasonography may be envisaged; in endemic areas, further studies are needed to describe and assess the usefulness of intestinal ultrasound in patients stratified by infection intensity and compared with markers such as calprotectin and fecal occult blood.

Schistosomiasis in immigrants, refugees and travellers in an Italian referral centre for tropical diseases.

BACKGROUND: Schistosomiasis is one of the most important neglected tropical diseases. If unrecognised and untreated, the chronic infection can lead to irreversible complications. METHODS: Retrospective observational study aimed at describing clinical history, laboratory findings and imaging presentation of imported schistosomiasis diagnosed at the Centre for Tropical Diseases, Sacro Cuore Don Calabria Hospital of Negrar, Verona, Italy from 2010 to 2014. The aim of our study was to assess differences in demographic characteristics, clinical presentation, laboratory data and ultrasound findings between immigrants/visiting friends and relatives (VFR) from endemic countries (endemic group) and expatriates/travellers (non-endemic group). RESULTS: A total of 272 patients were retrieved: 234 in the endemic and 38 in the non-endemic group. Most of the patients acquired schistosomiasis in Africa (97.4%). Symptoms were reported by 52.9% of the patients; abdominal pain (36%), macroscopic hematuria (11.3%), and genito-urinary symptoms (7.4%) being the most frequently reported. Increased IgE and blood eosinophilia were observed in 169 (63.8%) and 130 (47.8%) patients, respectively. The proportion of positive serology was 250/272 (91.9%).The Circulating Cathodic Antigen CCA for Schistosoma mansoni was positive in 14/61 individuals (23%). At microscopy, infected subjects were 103/272 (37.9%). The species of Schistosoma found were S. haematobium (47.6%), S. mansoni (46.6%) or both (5.8%). Schistosomiasis was classified as confirmed in 103 (37.9%), probable in 165 (60.6%) and suspected in 4 (1.5%) cases using clinical presentation, laboratory data and ultrasound findings. The infection was further classified based on organ involvement: intestinal (17.9%), hepatosplenic (5.1%), urogenital (48.9%), and indeterminate (43.8%). The comparative analysis of endemic and non-endemic patients highlighted differences in sex and age. Endemic patients had more frequent ova identification (41.9% vs. 13.2%, P < 0.001) and increased IgE (70% vs. 26.3%, P < 0.001) when compared with non-endemic. Multivariate analyses showed that younger age, abnormal ultrasound findings and blood eosinophilia were significantly associated with positive microscopy (OR = 0.94, OR = 2.12, OR = 1.98, respectively). CONCLUSIONS: Symptoms, eosinophilia and abnormal ultrasound findings were present in about half of patients, without differences between groups. Many patients had positive serology but negative microscopy, indicating that schistosomiasis might be misdiagnosed. A combination of diagnostic tools may facilitate the diagnosis.

Extended screening for infectious diseases among newly-arrived asylum seekers from Africa and Asia, Verona province, Italy, April 2014 to June 2015.

Background and aimManagement of health issues presented by newly-arrived migrants is often limited to communicable diseases even though other health issues may be more prevalent. We report the results of infectious disease screening proposed to 462 recently-arrived asylum seekers over 14 years of age in Verona province between April 2014 and June 2015. Methods: Screening for latent tuberculosis (TB) was performed via tuberculin skin test (TST) and/or QuantiFERON-TB Gold in-tube assay and/or chest X-ray. An ELISA was used to screen for syphilis. Stool microscopy was used to screen for helminthic infections, and serology was also used for strongyloidiasis and schistosomiasis. Screening for the latter also included urine filtration and microscopy. Results: Most individuals came from sub-Saharan Africa (77.5%), with others coming from Asia (21.0%) and North Africa (1.5%). The prevalence of viral diseases/markers of human immunodeficiency virus (HIV) infection was 1.3%, HCV infection was 0.85% and hepatitis B virus surface antigen was 11.6%. Serological tests for syphilis were positive in 3.7% of individuals. Of 125 individuals screened for TB via the TST, 44.8% were positive and of 118 screened via the assay, 44.0% were positive. Of 458 individuals tested for strongyloidiasis, 91 (19.9%) were positive, and 76 of 358 (21.2%) individuals from sub-Saharan Africa were positive for schistosomiasis. Conclusions: The screening of viral diseases is questionable because of low prevalence and/or long-term, expensive treatments. For opposing reasons, helminthic infections are probably worth to be targeted by screening strategies in asylum seekers of selected countries of origin.

The hidden epidemic of schistosomiasis in recent African immigrants and asylum seekers to Italy.

The prevalence of schistosomiasis among recent refugees from sub-Saharan Africa in Italy is unknown. This is a retrospective review of African immigrants screened at Centre for Tropical Diseases of Negrar from March 2014 to February 2016. Of the 373 immigrants tested, 34% were positive at least at one schistosomiasis test. The proportion of positive ELISA serology was 103/373 (27.6%). At microscopy, infected subjects were 65/373 (17.4%), (51% Schistosoma haematobium, 38% Schistosoma mansoni, 11% both). CCA antigen for S. mansoni was positive in 47/373 individuals (12.6%). We found a particularly high positivity rate in subjects from Mali (72.1%) and Ivory Coast (48%). This "hidden epidemic" of schistosomiasis cannot be longer neglected, considering the risk of severe complications, and the effective and inexpensive treatment available.

Chest ultrasound findings in pulmonary tuberculosis.

In resource-limited countries, the diagnosis of pulmonary tuberculosis (TB) is based on clinical findings, chest radiography and the demonstration of acid-fast bacilli in sputum. Few data are available on the use of ultrasound (US) to diagnose pulmonary TB. Chest US was performed in patients with lung TB from a rural African setting, to look for signs of the disease and to clarify the role US may have in the diagnosis of pulmonary TB. Sixty adult patients diagnosed with lung TB underwent chest US. All patients had abnormal findings. The most frequent was a subpleural nodule (SUN), which was mostly multiple and also found in radiologically normal areas. Other findings were lung consolidations, cavitations, miliary patterns made of miniature SUNs, and pleural and pericardial effusions. Chest US is a complementary tool in evaluating patients with suspected lung TB in resource-limited settings where the disease has high prevalence.

Pulmonary nodules in African migrants caused by chronic schistosomiasis.

Schistosomiasis is a neglected tropical disease that can cause mainly hepatic and genitourinary damage, depending on the species. Involvement of the lungs has been commonly described in acute infection (Katayama syndrome) and chronic infection (pulmonary hypertension). Although rarely reported in the scientific literature, cases of lung nodules due to chronic schistosome infection are also possible and are probably more frequent than commonly thought. Here we report seven cases of African migrants who were diagnosed with chronic schistosomiasis and pulmonary nodules due to deposition of schistosome eggs, and we compare our findings to the case reports found in the scientific literature. We discuss the management of these patients in a non-endemic setting, beginning with a first fundamental step that is to include parasitic infections, namely schistosomiasis, in the differential diagnosis of pulmonary nodules in African immigrants. All patients responded to antiparasitic treatment with praziquantel after a relatively short time. We therefore conclude that lung biopsies and other invasive procedures (performed in the first cases to rule out other potential causes, such as tuberculosis or malignant nodules) can be avoided or postponed.

Early hyperreactive malarial splenomegaly and risk factors for evolution into the full-blown syndrome: a single-centre, retrospective, longitudinal study.

BACKGROUND: The hyperreactive malarial splenomegaly (HMS) represents a chronic, potentially fatal complication of malaria. Case definition includes: gross splenomegaly, high level of anti-malarial antibody and IgM, response to long-term anti-malarial prophylaxis. In this study, a large series of patients not fully meeting the case definition was tentatively classified as early hyperreactive malarial splenomegaly (e-HMS). The main research questions was: does "e-HMS" tend to evolve to the full-blown syndrome? And if so, what are the main factors influencing this evolution? METHODS: Retrospective, longitudinal study. The patient database was searched to retrieve all potentially eligible patients. e-HMS was defined by splenomegaly of any size (with or without raised IgM), high anti-malarial antibody titre and exclusion of other causes of splenomegaly. The clinical outcome at following visits was analysed in relation to re-exposure to malaria, and to treatment (only part of the patients with e-HMS were treated with a single anti-malarial treatment and advised to follow an effective anti-malarial prophylaxis, if re-exposed). The association of the outcome with the main independent variables was first assessed with univariate analysis. A stepwise logistic regression model was then performed to study the association of the outcome with the main independent variables. RESULTS: One hundred and twenty-six subjects with e-HMS were retrieved. Eighty-one had at least one follow-up visit. Of 46 re-exposed to malaria for a variable period, 21 (46 %) had progressed, including 10/46 (22 %) evolving to full-blown HMS, while of 29 patients not re-exposed, 24 (93 %) had improved or cured and five (7 %) progressed (p < 0.001). At logistic regression re-exposure was confirmed as a major risk factor of progression (OR 9.458, CI 1.767-50.616) while treatment at initial visit was protective (OR 0.187, CI 0.054-0.650). CONCLUSION: e-HMS should be regarded as a clinical condition predisposing to HMS. Although the case definition may include false positives, e-HMS should be treated just as the full-blown syndrome. A single anti-malarial treatment is probably adequate, followed by effective prophylaxis for patients exposed again to malaria transmission.

Imported loiasis in Italy: an analysis of 100 cases.

BACKGROUND: loiasis is a neglected filariasis, affecting millions of individuals living in the rainforest areas of West and Central Africa. Aim of this study was to compare clinical and parasitological manifestations of loiasis between subjects born in endemic areas and expatriates/travelers. METHODS: we report clinical and parasitological manifestations of 100 patients with imported loiasis seen between 1993 and 2013 at the Center of Tropical Diseases, Negrar, Italy. RESULTS: among the 100 patients, 30 were African immigrants, 70 were Europeans (59 long-term expatriates and 11 travelers). Thirty-five patients (19 Africans and 16 Europeans) had positive microfilaremia. Calabar swellings were twice as frequent in Europeans (90%) than in Africans (46.7%), while a history of "eyeworm" was recorded in a higher proportion of Africans (43.3%) than in Europeans (17.4%). The median duration of exposure in the non-endemic group was also fairly long (14.6 years). Different drug regimens were used for treatment. CONCLUSIONS: we suggest that the differences between Africans and Europeans are more likely to be related to genetic differences, rather than to chronicity. Moreover the management of imported loiasis needs standardization.

Randomized clinical trial on ivermectin versus thiabendazole for the treatment of strongyloidiasis.

BACKGROUND: Strongyloidiasis may cause a life-threatening disease in immunosuppressed patients. This can only be prevented by effective cure of chronic infections. Direct parasitologic exams are not sensitive enough to prove cure if negative. We used an indirect immune fluorescent antibody test (IFAT) along with direct methods for patient inclusion and efficacy assessment. METHODOLOGY/PRINCIPAL FINDINGS: Prospective, randomized, open label, phase III trial conducted at the Centre for Tropical Diseases (Verona, Italy) to compare efficacy and safety of ivermectin (single dose, 200 µg/kg) and thiabendazole (two daily doses of 25 mg/Kg for two days) to cure strongyloidiasis. The first patient was recruited on 6(th) December, 2004. Follow-up visit of the last patient was on 11(th) January, 2007. Consenting patients responding to inclusion criteria were randomly assigned to one of the treatment arms. Primary outcome was: negative direct and indirect (IFAT) tests at follow-up (4 to 6 months after treatment) or subjects with negative direct test and drop of two or more IFAT titers. Considering 198 patients who concluded follow-up, efficacy was 56.6% for ivermectin and 52.2% for thiabendazole (p = 0.53). If the analysis is restricted to 92 patients with IFAT titer 80 or more before treatment (virtually 100% specific), efficacy would be 68.1% for ivermectin and 68.9% for thiabendazole (p = 0.93). Considering direct parasitological diagnosis only, efficacy would be 85.7% for ivermectin and 94.6% for thiabendazole (p = 0.21). In ivermectin arm, mild to moderate side effects were observed in 24/115 patients (20.9%), versus 79/108 (73.1%) in thiabendazole arm (p = 0.00). CONCLUSION: No significant difference in efficacy was observed, while side effects were far more frequent in thiabendazole arm. Ivermectin is the drug of choice, but efficacy of single dose is suboptimal. Different dose schedules should be assessed by future, larger studies. TRIAL REGISTRATION: Portal of Clinical Research with Medicines in Italy 2004­004693­87

Imported malaria in immigrants to Italy: a changing pattern observed in north eastern Italy.

BACKGROUND: Seventy percent of imported malaria cases in Italy occur in immigrants, generally with milder clinical presentation due to premunition acquired through repeated infections. Nevertheless, premunition could be progressively lost after a long period of nonexposure. We investigated the changing pattern of malaria in immigrants in two definite 5-year periods one decade apart. METHODS: We retrospectively examined the main laboratory findings of all malaria cases observed in immigrants from 1990 to 1994 and from 2000 to 2004. We stratified patients by reason for traveling: subjects in Italy who traveled to visit friends and relatives (VFR) or new immigrants (NI). RESULTS: Forty-eight cases of malaria in immigrants occurred from 1990 to 1994, while 161 were observed from 2000 to 2004. Patients admitted in the latter period had a significantly higher parasitemia (median 6,298 vs 3,360 trophozoites/microL, p= 0.028) and lower platelet count (median 96.5 vs 132 x 10(9)/L, p= 0.012) and hemoglobin (median 12.6 vs 13.4 g/dL, p= 0.049). While NI did not show any significant difference in the two study periods, in the VFR subgroup a higher parasitemia (median 8,845 vs 2,690 trophozoites/microL, p= 0.003) and lower platelet count (median 96 vs 131 x 10(9)/L, p= 0.034) were observed during the second period, during which three cases of severe malaria occurred in VFR. A longer stay in Italy was reported in VFR admitted during the second study period (median 8.3 vs 5.7 years). CONCLUSIONS: We found a changing pattern of malaria presentation in immigrants over a decade. The most likely explanation is the longer average stay outside endemic countries and subsequent loss of premunition observed in the second cohort. Immigrants living in Italy for some time and traveling to VFR should no more be considered a low-risk group for severe malaria. Pretravel advice should be particularly targeted to this group.

Hepatitis A, B, and C infection in a community of sub-Saharan immigrants living in Verona (Italy).

BACKGROUND: In Italy, about 5% of the population is represented by immigrants. The epidemiology of hepatitis A virus (HAV), hepatitis B virus (HBV), and hepatitis C virus (HCV) infection in Africa is very different from Europe; the present study aimed to assess the seroprevalence of viral hepatitis infections in sub-Saharan African immigrants living in Verona. METHODS: A total of 182 illegal immigrants were interviewed concerning sociodemographic characteristics and epidemiological information. Their serum was tested for anti-HAV [immunoglobulin (Ig) G and IgM], HBV (HBsAg, anti-HBs, anti-HBc, HBeAg, and anti-HBe), and HCV (anti-HCV) markers. RESULTS: The immigrants (age: 3 mo-60 y) were mostly single and males, with a higher education; only 50% of them declared having a regular job. Anti-IgG HAV+ prevalence was 99.5% (100% HAV positivity in the younger age bracket). As for HBV, 67.6% (123) of the immigrants were naturally infected and 9.3% had chronic infection; 4.4% were anti-HBs+ isolated (vaccinated). For HBV infection (any HBV marker), a significant difference was only found for increasing age ( p < 0.01) and married people ( p < 0.001). A statistically significant prevalence of HBsAg was found among the unemployed ( p < 0.001) and those with a lower education ( p < 0.05). Five cases (2.7%) resulted in HCV+ with no reported specific risk factors and with no significantly different sociodemographic features; these people tended to report a low level of education and unemployment. CONCLUSIONS: HAV and HBV positivity is higher than in the autochthonous population. While HAV positivity merely represents past infection, the high prevalence of HBsAg in immigrants and the presence of HBsAg/HBeAg in the same group may represent a risk for HBV transmission. The HCV positivity rate resulted similar to the prevalence of the Italian population.

Imported malaria in adults and children: epidemiological and clinical characteristics of 380 consecutive cases observed in Verona, Italy.

BACKGROUND: Since the year 2000, in Italy, there has been a constant decrease in the number of cases of imported malaria in immigrants. Nevertheless, immigrants still account for about 70% of reported cases. To our knowledge, no data are yet available on imported malaria in children. This paper describes the main characteristics of malaria cases observed in recent years in the three main hospitals in Verona (roughly representing 10% of all cases reported in Italy in the period), with a special focus on the poorly known problem of imported malaria in children. METHOD: All malaria cases occurring from 2000 to 2004 were retrospectively examined. Semi-immune and nonimmune patients were analyzed for clinical, laboratory, and parasitological findings. A separate analysis was carried out for children who traveled to endemic areas to visit relatives and friends (VRF) and children born in endemic countries who came to Italy for immigration purposes. RESULTS: A total of 380 cases of imported malaria occurred in Verona in the 5-year period, 43 being children. Semi-immune patients had a significantly lower parasitemia (p = 0.0032) and parasite clearance time and significantly shorter fever duration than nonimmune (p = 0.025 and p = 0.0026). VRF children presented significantly higher parasitemia and significantly lower platelet count (p = 0.016 and p = 0.042) than recent immigrants. Parasitemia clearance time and fever duration were longer in VRF children than in recent immigrants (p = 0.014 and p = 0.0085). We observed 23 cases of severe malaria, including 4 cases in immigrants. CONCLUSIONS: Our data confirm a significant difference both in clinical and in parasitological findings between semi-immune and nonimmune patients. We identified two populations of immigrant children: semi-immune (recent immigrants) and nonimmune (VRF). The latter is a high-risk group for severe malaria. Educational actions should be specially designed for immigrants traveling to VRF, focusing on the risk of severe malaria for both adults and children.

Evaluation of an indirect immunofluorescence assay for strongyloidiasis as a tool for diagnosis and follow-up.

The diagnostic accuracy of an indirect immunofluorescence antibody test (IFAT) for Strongyloides stercoralis at different serum antibody titers was evaluated. To assess diagnostic sensitivity, sera from 156 patients with known strongyloidiasis were collected. Negative control sera were obtained from a composite group of 427 subjects (blood donors and hospitalized patients). With an area under the receiver-operating characteristic plot of 0.98, the IFAT showed a high level of diagnostic accuracy for strongyloidiasis. An antibody titer of > or = 1:20, with 97% sensitivity and 98% specificity, was identified as the diagnostic threshold with the best overall performance. Cross-reactions were evaluated with 41 additional samples from patients with other known helminth infections, and the IFAT detected low-titer positivity in only one subject with filariasis. A positive IFAT result at an antibody dilution of > or = 1:80 was virtually 100% specific, with 71% sensitivity. To test the usefulness of the IFAT as a monitoring tool, the changes in specific-antibody titers after treatment in a group of 155 patients were evaluated. Seroreversion or a decrease in antibody titer of twofold or more was observed in 60% of the patients. Response to treatment was directly correlated to the initial antibody titer, and a baseline titer of > or = 1:80 was identified as the best predictor of response. In conclusion, a positive IFAT result at an antibody dilution of >/=1:20 is the optimal cutoff for screening. A titer of > or = 1:80, with virtually no false-positive result, is a reliable cutoff for a serological assessment of treatment efficacy and for inclusion in clinical trials.