Further studies on prevalence of hydatidosis in slaughtered animals from North Jordan

Examination of 471 sheep, 118 goats, 157 cattle and 56 camels slaughtered in abattoirs in North Jordan was carried out during March–May 1984. Drought conditions that prevailed during the preceding winter led to slaughtering old female sheep (4 years) due to scarcity of food, which allowed us to analyse the prevalence of hydatidosis in various age groups of sheep. An overall infection rate of 27.8, 1.7, 5.8 and 10.7 percent was found in sheep, goats, cattle and camels, respectively. The infection rate was as low as 1.5 percent in male and 1.9 percent in female sheep under 2 years of age. However, the rate of hydatid infection increased with age and reached as high as 63.7 percent in ewes 4 years of age and older. The percentage of animals with fertile cysts was also highest in sheep (68.7 percent of infected animals) and increased with age reaching 100 percent in ewes which were 10 years of age or older. Analysis of all cysts recovered from the livers and lungs of infected ewes from various age groups revealed a sharp increase in the mean total number of cysts in age groups over 8 years of age. The fertility rate of the cysts in the liver was significantly greater in ewes 6 years old or more (64.8–78.6 percent) than in younger age groups (8.7–46.2 percent). In the lung, the fertility rate increased progressively with age reaching as high as 97.9 percent in ewes 10 years old or more. These findings of high infection and fertility rates of hydatid disease in sheep, particularly of older age groups, prompt plans for further epidemiological studies and control programmes.     

Serodiagnosis of sheep hydatidosis with hydatid fluid, protoscolex, and whole body of Echinococcus granulosus antigens

Diagnosis of hydatidosis is based on immunodiagnostic methods along with radiological and ultrasound examinations. A great number of immunological assays have been developed for detection of anti-hydatid cyst antibodies. The principal intermediate host of Echinococcus granulosus in most endemic regions of the world is sheep. Antibodies to various antigens are detectable in the sera of some, but not all infected sheep. The objective of the present study was to develop a specific and simple antigen-based ELISA method for diagnosis of hydatidosis in sheep with different (hydatid fluid, protoscolices, and whole body of E. granulosus) antigens. A total of 100 sera were collected from sheep with hydatidosis proven by inspection of hydatid-infested livers and lungs of the sheep slaughtered in Mashhad abattoir. Hydatid fluid and protoscolex were isolated from livers or lungs of sheep with hydatid cyst in sterile conditions. Whole body of E. granulosus was isolated from intestine of infected dogs. Sera samples were examined by ELISA with different antigens. The results of antibody detection by indirect ELISA, using different antigens, showed that the hydatid fluid was the most effective antigen of those assessed for detection of infection with hydatidosis in sheep. Findings of this study indicated that antibody detection assay is a sensitive approach for diagnosis of hydatid cyst in sheep.     

Basophil releasability in human hydatidosis.

We studied immunoglobulin E (IgE)- and non-IgE-mediated releasability in basophils from 31 patients with hydatidosis. Histamine release to non-IgE-dependent stimuli did not differ significantly between normal individuals and patients with hydatidosis. On the contrary, an increased histamine liberation was obtained by challenging basophils from hydatid patients with anti-human IgE. It is concluded that Echinococcus granulosus infection induces an enhanced sensitivity of basophils to IgE-dependent stimuli.     

Serodiagnosis of human leptospirosis by counterimmunoelectrophoresis.

The counterimmunoelectrophoresis (CIE) technique employing a soluble extract antigen was found useful in screening human sera for antileptospiral antibodies to multiple leptospiral serovars. The CIE test results with sera from patients with suspected cases of leptospirosis and sera from a control group compared favorably (97.9%) with those obtained by the microscopic agglutination test using a battery of live leptospiral antigens. CIE is easy to perform, is highly sensitive, uses an antigen which is very stable at room temperature, and permits the screening of many sera in a short period of time. The CIE technique appears to be ideally suited to a small laboratory where facilities may be too limited for examining sera by the microscopic agglutination test.     

Spectrotypic analysis of humoral response in human hydatidosis.

The spectrotypic patterns of anti-Echinococcus granulosus and anti-F(ab')2 antibodies were analysed in 13 patients with different forms of hydatidosis by means of isoelectric focusing (IEF). Specific anti-echinococcus antibodies and specific echinococcus antigens were obtained by crossed affinity chromatography between patient serum and cyst fluid, as previously described (D'Amelio et al., 1985). A wide spectrotype in the pattern of anti-Echinococcus antibodies was observed, with strong homologies among the different sera mainly at acid and neutral pH. One serum displayed faint, nearly inapparent bands. Conversely, the pattern of anti-F(ab')2 antibodies in the six patients in whom they were positive was limited but heterogeneous, ranging from monoclonal through oligoclonal to polyclonal. A predominant clone was identified in the patient with a polyclonal pattern. A correlation between qualitative IEF spectrotypic patterns and the quantitative results of immunoenzymatic assays was observed for both types of antibodies.     

Histamine release test in the diagnosis of human hydatidosis

An evaluation of the use of the histamine release test (HRT) in the diagnosis of human hydatidosis is presented. This technique, which makes it possible to evaluate directly IgE dependent immediate hypersensitivity by measuring the histamine released from leucocytes (basophils) after antigenic challenge, was compared with the detection of serum specific IgE by the radio-allergosorbent test (RAST), and with the determination of serum specific IgE by the enzyme-linked immunosorbent assay (ELISA). Of the 54 patients with hydatidosis, all were positive according to HRT, 42 according to RAST and 47 according to ELISA. No false positive results were obtained by HRT in 43 patients with parasitosis other than hydatidosis, however, of these 43, 10 resulted in false positives according to RAST and five according to ELISA. It is concluded that HRT is more sensitive and more specific than RAST and ELISA.     

Praziquantel in human hydatidosis. Evaluation by preoperative treatment

The efficacy of praziquantel has been studied in human hydatic disease due to E. granulosus, using parasitological and pharmacological criteria of improvement. This evaluation uses a prospective therapeutic trial in 15 patients with one or several hydatic cysts in different sites. Before surgery, nine of these received daily 75 mg/kg of praziquantel in 2 courses of 10 days each. The other six patients are considered as controls. The protoscolices vitality is determined by direct optic microscopy and by intraperitoneal mouse inoculation. According to the results of optic microscopy, praziquantel sterilizes hydatic cysts: 19 sterilized cysts out of 26 coming from treated patients, and 4 out of 11 in control group. This effect seems to be emphasized in hepatic localization. Nevertheless, according to the results of mouse inoculation, praziquantel does not significantly reduce the pathogenicity of inoculated proscolices and germinal layer: 11 mice out of 39 are healthy in the treated group, and 5 out of 15 in controls. Moreover, the determination with a fluorimetric method has not detected praziquantel in the hydatid liquid issued from treated patients. The drug does not pass through the cyst wall, and so, cannot have a scolicidal activity. Praziquantel cannot be considered as a medical treatment in human hydatidosis.     

Analysis of proteins, helper dependence, and seroepidemiology of a new human parvovirus

A new type of defective parvovirus, tentatively designated as adeno-associated virus type 5 (AAV-5), is characterized as far as its proteins, its helper dependence, and its seroepidemiology are concerned. The protein analysis of AAV-5 in polyacrylamide gels demonstrated the presence of three structural polypeptides, corresponding to VP 1, VP 2, and VP 3 of other AAV types. The preparation of monoclonal antibodies against AAV-5 permitted the analysis of viral structural antigen expression by using adenovirus type 12 (Ad 12) or several herpes group viruses as helper viruses, respectively. AAV-5-infected cell cultures coinfected with either Ad 12, Herpes simplex virus (HSV), Cytomegalovirus (CMV), or Varicella Zoster virus (VZV) efficiently synthesize AAV-5 specific antigens. Epstein-Barr virus (EBV) and Herpesvirus saimiri, in contrast, provide only a very weak helper activity for AAV 5 antigen expression. The development of a specific ELISA test permitted screening of human sera for antibodies to AAV-5. Forty-five percent of 926 sera from all age groups and approximately 60% of the adult population reveal antibodies to structural components of this virus. The seroepidemiology differs from that reported for other AAV serotypes. Highest average titers against AAV-5 are observed in the age group between 15 and 20 years. Sera from patients with cervical carcinoma revealed average titers of antibodies well below those of age-matched control groups. Attempts to find higher antibody levels against AAV-5 in specific human diseases failed thus far.     

Serodiagnosis of human and animal pythiosis using an enzyme-linked immunosorbent assay.

Conventional serodiagnosis of Pythium insidiosum infections involves the use of the immunodiffusion (ID) test. This test specifically diagnoses human and animal pythiosis. The test, however, has limited sensitivity and does not detect some culturally proven cases of the disease. Because of the increased recognition of pythiosis among humans and animals, we developed and evaluated an enzyme-linked immunosorbent assay (ELISA) using a soluble antigen from broken hyphae of P. insidiosum. Studies were carried out with sera from five humans and eight animals with culturally and/or histologically proven pythiosis. Some of these sera were negative in the ID test for pythiosis. Heterologous case sera from thirteen humans and two horses, plus 5 sera from healthy humans and 17 from healthy animals, were tested. Of the pythiosis case sera tested, the ID test detected only 8 of 13 (61.5%), whereas the ELISA detected all of them (100%). The ID and ELISA tests were entirely specific and gave negative results or low titers respectively, with sera from humans and animals with heterologous fungal infections or with no apparent illness. No correlation was found between the height of the ELISA titers and negative or positive sera in the ID test. Our results indicate that the ELISA is a reliable serodiagnostic test for pythiosis. It is as specific as the ID test but more sensitive.     

Geographical differences in human herpesvirus 8 seroepidemiology: a survey of 1,201 individuals in Asia

Since the discovery of human herpesvirus 8 (HHV8) as a contributory cause of Kaposis sarcoma, the clinical role of this virus has been actively investigated. An understanding of HHV8 seroepidemiology is critical for the study of its pathogenesis within a specific environment. A sero-survey is described in Taiwan of 1,201 individuals ranging in age from under 1 year to over 70. Indirect immunofluorescence assay was used to determine antibody titers against both latent and lytic antigens of HHV8. The results indicate that very few individuals (3-4%) were exposed to HHV8 before 10 years of age. Infection rate peaked (19.2%) between the ages of 21 to 40. Females showed a slightly higher seroprevalence for HHV8 than males, but the difference was not statistically significant. Pregnancy did not correlate with increased HHV8 infection rate nor with augmented HHV8 antibody titers. It is concluded that HHV8 in Taiwan is predominantly an infectious agent for adults. In this geographical locale, HHV8 is similar to herpes simplex virus type 2 in its likely transmission occurring presumptively through sexual routes. However, the study also indicates that a smaller portion of HHV8-transmission could occur through nonsexual contacts.     

Flubendazole in human Echinococcus granulosus hydatidosis. Preoperative care: parasit-pharmacologic study

The effect of flubendazole in human hydatic disease due to E. granulosus has been studied in 22 patients with one or several hydatic cysts of different sites. Flubendazole has been given orally before surgery for a 10 days mean period, at 4 g daily in adults and 1 g daily in children. Flubendazole has been titrated by radioimmuno-assay in sera, urines and bile taken 12 to 24 hours after the last ingestion and in the hydatic cyst (membranes and liquid). The scolex vitality was determined by direct optic microscopy and by intra-peritoneal mouse inoculation. Seven non-treated patients, without hydatic disease, were considered as controls. The flubendazole concentrations in sera (3.01 +/- 3.73 ng/ml) and in urines (7.6 +/- 7.5 ng ml) are low. They are also low in membranes (3.21 +/- ng/mg) and in hydatic liquid, but significantly more elevated in the hepatic localisation than in the pulmonary localisation. The bile concentrations are high (167.9 +/- 133.2 ng/ml). There is no correlation between these concentrations and the amounts of flubendazole administered. The scolex vitality was correlated neither with the amounts of flubendazole administered, nor with the concentrations of flubendazole in the hydatic cyst. Further studies are necessary before judging of the efficacy of flubendazole in the human hydatic disease.     

European seroepidemiology network 2: Standardisation of assays for seroepidemiology of varicella zoster virus.

BACKGROUND: The aim of the European Sero-Epidemiology Network (ESEN2) is to harmonise the serological surveillance of vaccine-preventable diseases in Europe. OBJECTIVE: To allow comparison of antibody prevalence in different countries by standardising results into common units. STUDY DESIGN: For varicella zoster virus (VZV), a reference laboratory established a panel of 148 samples, characterised by indirect enzyme-immunoassay (ELISA), indirect immunofluorescence, and complement fixation test. Fifty-seven samples were also studied by the fluorescence antibody to membrane antigen test. The geometric mean of the antibody activity (GMAA) obtained from four ELISA determinations was used to characterise each sample of the panel as positive (GMAA: >100 mIU/ml), equivocal (GMAA: 50-100 mIU/ml) or negative (GMAA: <50 mIU/ml) for antibody to VZV (anti-VZV). Thirteen laboratories, using five different ELISA tests, tested the panel. RESULTS: Agreement with the reference laboratory was above 85% in all cases, and the R(2) values obtained from regression analysis of the quantitative results were always higher than 0.87. Finally, the regression equations could be used to convert national values into a common unitage. CONCLUSION: This study confirmed that results for anti-VZV obtained by different ELISA methods can be converted into common units, enabling the comparison of the seroprevalence profiles obtained in the participant countries.     

Post operative surveillance of human hydatidosis: evaluation of immunodiagnostic tests.

We investigated the kinetics of antibodies detected by indirect hemagglutination (IHA), IgE Elisa and immunoelectrophoresis (IEP) in patients with hydatid disease operated on and continuously followed in the pre-operative and post-operative periods. In the pre-operative phase the IgE Elisa test was found to be adequately sensitive (68.4%) compared with IHA (79%), with a ratio of IgE Elisa/IHA positivity of 87%, while IEP was positive in 55.3% of cases (IEP/IHA ratio = 70%). During post-operative follow-up IHA became negative late in patients who were cured (7 out of 11 were still positive after 4 yrs), whereas IEP and IgE Elisa became negative within 2 yrs of operation (apart from 1 patient with a persisting positive IgE Elisa 3 yrs later). However, IgE Elisa appeared clearly more sensitive in revealing postoperative recurrences (13 out of 13 patients had positive IgE Elisa, vs. 6 out of 13 IEP).     

The seroepidemiology of tetanus in Catalonia,Spain

Titres of anti-tetanus toxin antibodies ≥0.1 IU/ml were determined using an enzyme linked immunosorbent assay in representative samples of the juvenile and adult population of Catalonia. The prevalence obtained in 1,316 juveniles and 1,296 adults was 99.4 and 68.3%, respectively. In adults, the prevalence in males (76.5%) was higher (P < 0.001) than in females (61.7%), fell with increasing age and was higher in subjects born in Catalonia (72.5%) than in those born outside Catalonia (57.9%) (P < 0.001). These results show that routine vaccination of children is successful. In adults aged ≥45 years, the prevalence is inadequate and efforts should be made to increase vaccination.