Performance of loop-mediated isothermal amplification (LAMP) for detection of Schistosoma mansoni infection compared with Kato-Katz and real-time PCR.

The performance of loop-mediated isothermal amplification (LAMP) for detection of Schistosoma mansoni DNA from stool and urine samples in comparison with Kato-Katz and real-time polymerase chain reaction (PCR) was studied. After obtaining informed consent, 50 children participated in the present study and agreed to submit stool and urine samples. Stool samples were examined by Kato-Katz. Both real-time PCR and LAMP techniques were applied on stool and urine samples. The overall prevalence of S. mansoni was 46% in stool and urine samples as detected by the employed techniques, and 90% of cases had light infection intensity. The highest percentage of infection was diagnosed by real-time PCR (44%), followed by Kato-Katz (42%) and LAMP in the stool (36%), while the lowest percentages of infection were diagnosed by real-time PCR and LAMP in urine samples (24% and 14%, respectively). Kato-Katz, real-time PCR and LAMP showed 100% specificity where the sensitivity was 91.3%, 95.7% and 78.3%, respectively, in stool samples. Real-time PCR and LAMP showed lower sensitivity in urine samples. The LAMP assay is a promising technique for S. mansoni diagnosis in endemic countries of moderate and high-intensity infection. Yet, it needs further optimization, particularly in urine samples.

Evaluation of two doses of triclabendazole in treatment of patients with combined schistosomiasis and fascioliasis.

To determine the safety and efficacy of 2 consecutive doses of triclabendazole (TCBZ) in the treatment of Schistosoma mansoni infection in human cases infected with both S. mansoni and Fasciola sp., we conducted a field survey involving 6314 individuals from 15 villages. The overall prevalence of schistosomiasis alone was 15.8%, of fascioliasis alone 2.2%, and of combined infection 0.7%. Treatment with 2 doses of TCBZ was given to the 49 cases with combined infection. Eight weeks after treatment, the cure rate was 96% for fascioliasis and was 32.7% for schistosomiasis. All schistosomiasis cases cured had a low intensity infection. Liver function tests done before treatment and 8 weeks after substantiate the safety of 2 doses of TCBZ given to those with combined infection. Administration of TCBZ should precede praziquantel in treatment of combined infection, however TCBZ cannot be recommended for infection with S. mansoni alone.

Ineffectiveness of myrrh-derivative Mirazid against schistosomiasis and fascioliasis in humans.

The present study assessed the schistosomicidal and fasciolicidal actions of the myrrh-derivative Mirazid in an area of low schistosomiasis transmission. A total of 27 patients infected with Schistosoma mansoni and 16 with Fasciola spp. received the maximum recommended dose of Mirazid. Pretreatment egg counts in 4 Kato-Katz slides were compared with similar counts in stool samples collected 1 and 2 months after treatment. Standard procedures and quality control measures were followed. The results revealed that Mirazid used as schistosomicidal or fasciolicidal agent in the maximum recommended dose has a low cure rate and produced a negligible reduction in egg counts. Prescribing such an ineffective drug in Egypt might endanger the achievements of the schistosomiasis control strategy.

Intra-specimen and day-to-day variations of Fasciola egg counts in human stools.

Intra-specimen and day-to-day variations of Fasciola egg counts in stools were investigated for 16 cases of established fascioliasis. For each case six Kato slides from a single stool sample were examined daily for 5 consecutive days. The results indicated the presence of significant intra-specimen variations in more than one-third of the examined series, while the inter-specimen variation was almost negligible. The sensitivity of the Kato-Katz test for diagnosing Fasciola infection with three Kato slides from the same specimen or on different days ranged from 96.0%-99.1%. The examination of three Kato smears from a single stool specimen, which is more feasible in field studies, would give an accurate diagnosis of fascioliasis. Used as such, the Kato-Katz technique is highly sensitive in the diagnosis of fascioliasis.

Specific IgG avidity in acute and chronic human fascioliasis.

The detection of IgG avidity in sera is potentially useful in the diagnosis of acute and chronic infection. We studied IgG avidity in 31 patients with fascioliasis, with the aim of evaluating the clinical application of this test to confirm the diagnosis of incubating cases and to distinguish between acute and chronic cases. Of the 31 cases, 13 were incubating and had a mean avidity index of 57.28 +/- 5.79%. The 18 chronic cases had an avidity index of 68.80 +/- 8.92%. The difference was highly significant. We conclude that IgG avidity is a reliable means of identifying the stage of fascioliasis and suggest a cut-off point of 59.90% to distinguish between acute and chronic infection.

Performance of IgG avidity in an area endemic for schistosomiasis in Egypt.

We assessed the performance of IgG avidity in the diagnosis of acute, chronic and recent (reinfection) on top of chronic schistosomal infections in patients treated with praziquantel. Immunoglobulin levels were studied in 111 patients with Schistosoma mansoni infection and 28 partially cured patients (not responding to the first dose of praziquantel treatment and almost cured after a second one). Before treatment all patients with schistosomiasis had elevated IgG levels, 75% of them also had increased IgM levels. Avidity index was high among all age groups. The increased IgM/IgG ratio and avidity index among children with schistosomiasis before treatment support the idea of reinfection. Treatment had no significant effect on the studied parameters. We conclude that unlike IgM and IgG antibody levels, IgG avidity test cannot be used to distinguish between recent and chronic infections.

Serum IgM. Does it relate to the level of chronicity in fascioliasis?

Serum IgM and IgG specific to human fascioliasis were reported to monitor prepatent and patent human infection respectively. Recently an assay measuring the antigen binding avidity of IgG antibodies was proved to be of value in identification of the stage of fascioliasis. The present study investigates the level of serum IgM in relation to avidity IgG, among acute and chronic Fasciola patients (using ELISA). Specific IgM antibody was detected in all acute and in 88% of chronic cases. IgM serum level was significantly higher in acute cases. IgG antibody was found in both acute and chronic cases but with no significant difference between the two groups. Regarding IgG avidity, it was found that acute cases had low IgG avidity index whereas chronic cases had significantly higher avidity. Four chronic patients had high IgM level and high IgG avidity. The egg counts as well were relatively high. The possibility of reinfection was considered in those cases.

The circumoval precipitin reaction in Fasciola. Detection of shell pores by scanning electron microscopy.

Precipitation reaction was detected around Fasciola eggs containing mature miracidia when they were incubated for 20 minutes with the sera of acute and chronic fasciolosis patients. The reaction was of the bleb type. The amount of blebs formed around the eggs was greater in case of acute than chronic fasciolosis. Scanning electron microscopy illustrated pores in the shell of Fasciola eggs. It is probable that the metabolic antigen passes through these pores leading to the positive circumoval precipitin reaction in cases of Fasciola infection. Antibodies specific to Fasciola excretory/secretory (E/S) egg antigens were not detected in the sera of Schistosoma cases.

Evaluation of Fasciola excretory-secretory (E/S) product in diagnosis of acute human fasciolosis by IgM ELISA.

Diagnosis of fasciolosis in the acute phase depends on a sensitive and accurate serological test. The present study is an evaluation of the efficacy of excretory-secretory Fasciola gigantica adult worm antigen by IgM ELISA. Thirty eight patients with acute fasciolosis and 14 in the chronic phase together with 23 patients with different parasitic infections were introduced in the study. Seventeen healthy, parasite free individuals, were served as controls. A crude excretory-secretory antigen and its fractions I and II (obtained by gel filtration chromatography on Sephadex G-200) were tested. The crude antigen revealed 100% sensitivity, 94% specificity and 98% accuracy at the cut off level of 0.3 in acute infection. It gave positive results in 77% of chronic cases. Cross reactions with Schistosoma and Toxoplasma were negligible. A significant positive correlation between IHA titres and ELISA O.D. readings was observed. Fractions I and II proved of no diagnostic significance. The test system F. gigantica E/S product by IgM ELISA is highly recommended for diagnosis of acute fasciolosis.

Detection of circulating E/S antigens in the sera of patients with fascioliasis by IELISA: a tool of serodiagnosis and assessment of cure.

An IELISA was developed to evaluate the performance of Fasciola E/S antigens in diagnosis and cure assessment of human Fasciola infection. Twenty patients with acute (prepatent) fascioliasis and another 20 with patent infection were enrolled in the study. Patients were treated with TCZ and followed at 1, 3 and 6 months after therapy. At inspection, the sensitivity of the test to diagnose prepatent cases was 100% compared to 70% for patent infections. There was a gradual decrease of antigenaemia over the follow-up period in acute cases. In chronic cases antigen disappeared from 13 cases (65%) at 1 month; this proportion did not change at 3 or 6 months.

Circulating antibodies and antigens correlate with egg counts in human fascioliasis.

We explored the relationships between specific IgG antibody levels and circulating E/S antigen to intensity of Fasciola infection in the human host. Twenty patients with patent infection and six healthy individuals were enrolled in the study. Intensity of infection was determined by repeated egg counts in stools, while IgG antibodies against adult Fasciola gigantica somatic FI, FII and against E/S antigens were measured as ELISA O.D. readings. The level of circulating E/S antigens was determined by IELISA. Positivity as well as levels of antibodies and antigen correlated with infection intensity. These findings may disclose in the future a relation between morbidity in the acute phase and worm load.

Evaluation of two doses of triclabendazole in treatment of patients with combined schistosomiasis and fascioliasis

To determine the safety and efficacy of 2 consecutive doses of triclabendazole [TCBZ] in the treatment of Schistosoma mansoni infection in human cases infected with both S. mansoni and Fasdola spv we conducted afield survey involving 6314 individuals from 15 villages. The overall prevalence of schistosomiasis alone was 15.8%, of fascioliasis alone 2.2%, and of combined infection 0.7%. Treatment with 2 doses of TCBZ was given to the 49 cases with combined infection. Eight weeks after treatment, the cure rate was 96% for fascioliasis and was 32.7% for schistosorniasis. All schistosomiasis cases cured had a low intensity infection. Liver function tests done before I treatment and 8 weeks after substantiate the safety of 2 doses of TCBZ given to those with combined infection. Administration of TCBZ should precede praziquantel in treatment of combined infection, however TCBZ cannot be recommended for infection with S. mansoni alone

Ineffectiveness of myrrh-derivative Mirazid against schistosomiasis and fascioliasis in humans

The present study assessed the schistosomicidal and fasciolicidal actions of the myrrh-derivative Mirazid in an area of low schistosomiasis transmission. A total of 27 patients infected with Schistosoma mansoni and 16 with Fasciola spp. received the maximum recommended dose of Mirazid. Pretreatment egg counts in 4 Kato-Katz slides were compared with similar counts in stool samples collected 1 and 2 months after treatment. Standard procedures and quality control measures were followed. The results revealed that Mirazid used as schistosomicidal or fasciolicidal agent in the maximum recommended dose has a low cure rate and produced a negligible reduction in egg counts. Prescribing such an ineffective drug in Egypt might endanger the achievements of the schistosomiasis control strategy

Intra-specimen and day-to-day variations of Fasciola egg counts in human stools

Intra-specimen and day-to-day variations of Fasciola egg counts in stools were investigated for 16 cases of established fascioliasis. For each case six Kato slides from a single stool sample were examined daily for 5 consecutive days. The results indicated the presence of significant intra-specimen variations in more than one-third of the examined series, while the inter-specimen variation was almost negligible. The sensitivity of the Kato-Katz test for diagnosing Fasciola infection with three Kato slides from the same specimen or on different days ranged from 96.0%-99.1%. The examination of three Kato smears from a single stool specimen, which is more feasible in field studies, would give an accurate diagnosis of fascioliasis. Used as such, the Kato-Katz technique is highly sensitive in the diagnosis of fascioliasis

Performance of IgG avidity in an area endemic for schistosomiasis in Egypt

We assessed the performance of IgG avidity in the diagnosis of acute, chronic and recent [reinfection] on top of chronic schistosomal infections in patients treated with praziquantel. Immunoglobulin levels were studied in 111 patients with Schistosoma mansoni infection and 28 partially cured patients [not responding to the first dose of praziquantel treatment and almost cured after a second one]. Before treatment all patients with schistosomiasis had elevated IgG levels, 75% of them also had increased IgM levels. Avidity index was high among all age groups. The increased IgM/IgG ratio and avidity index among children with schistosomiasis before treatment support the idea of reinfection. Treatment had no significant effect on the studied parameters. We conclude that unlike IgM and IgG antibody levels, IgG avidity test cannot be used to distinguish between recent and chronic infections