Clinical observation of meconium peritonitis.

Twenty cases of meconium peritonitis were found between September 1980 and March 1988 at Mackay Memorial Hospital. The male to female ratio was 1.5 to 1. Six of the 20 cases involved premature babies. The great majority presented symptoms and signs before 5 days old, but one case was not diagnosed until 13 months of age. Polyhydramnios of the mother was found in six cases (30%). Abdominal distension was the universal symptom in all 20 cases. Hydrocele was noticed in 8 of the 12 male babies. In seven cases (35%) radiological examination showed abdominal calcifications. All patients underwent surgical intervention. Peritonitis was of cystic type in seven cases (35%); fibroadhesive in nine cases (45%); generalized in four cases (20%). Evident intestinal perforation was noted in 13 patients, and a mechanical obstructive lesion was found in 9 cases (45%) including intestinal diaphragm, atresia, volvulus, and Hirschsprung's disease. In only two patients (10%) was neither evident perforation nor obstructive lesion. The overall mortality rate was 30% (6/20), with no mortality after 1986 (0/6). The mortality seemed increased in those associated with perforation (4/13) and midgut volvulus (2/2) in particular, compared with non-perforation cases (1/7). It appears that early aggressive operation, and meticulous postoperative care, have contributed to the higher survival rate in recent years.

A novel anthelmintic model utilizing jirds, Meriones unguiculatus, infected with Haemonchus contortus.

Currently, no in vivo laboratory model is available for evaluating anthelmintics against the important ruminant helminth Haemonchus contortus. This report outlines a novel anthelmintic assay utilizing immunosuppressed (0.02% hydrocortisone in feed) jirds, Meriones unguiculatus, infected with H. contortus. Immunosuppressed jirds were inoculated with approximately 1,000 exsheathed infective larvae of H. contortus, treated per os on day 10 postinoculation (PI), and necropsied on day 13 PI. Each stomach was removed, opened longitudinally, incubated in distilled water at 37 C for 5 hr, fixed in formaldehyde solution, and stored for subsequent examination. Stomach contents were examined using a stereomicroscope (15-45x). A variety of standard anthelmintics has been evaluated in the model; modern broad-spectrum ruminant anthelmintics (benzimidazoles, febantel, ivermectin, levamisole hydrochloride, and milbemycin D) are active uniformly and in most cases at doses (mg/kg) comparable to those required for efficacy against H. contortus in ruminants. This model provides an important new tool to assess preliminarily the activity of experimental drugs against H. contortus in vivo prior to studies in ruminants and also may provide a useful tool for studying host-parasite interactions for H. contortus.

Bronchoalveolar eosinophilia in guinea pigs harboring inapparent infections of Paraspidodera uncinata.

During the course of experiments examining the changes in cell populations in bronchoalveolar lavage (BAL) fluid in 3-11-wk-old guinea pigs, a marked increase in the numbers of eosinophils was observed in BAL fluid in untreated control animals from historical levels (observations made over the previous 2 yr) of 8.8 +/- 1.5% to levels greater than 16% and up to 44%. Repeated occurrence of this phenomenon in several different groups of guinea pigs that appeared clinically normal and the impact on our experimental studies led us to attempt to identify the cause of increased inflammatory cell numbers in these guinea pigs. Examination in 2 groups of animals of whole blood and lung tissue for the presence of bacteria or fungi revealed minor bacterial infections in one group but not the other, whereas both exhibited elevated eosinophil numbers. At necropsy, 41.7% and 60% of the animals in the 2 groups harbored the nematode Paraspidodera uncinata. Guinea pigs exhibiting eosinophil numbers in BAL fluid comparable to our historical levels were then inoculated with approximately 100 embryonated eggs of P. uncinata and developed elevated eosinophilia in BAL fluid compared to sham-inoculated animals (significant at 2 of the 3 examination times postinoculation). These findings suggest that P. uncinata is capable of causing changes in inflammatory cell populations in the lungs of guinea pigs and illustrate the importance of subclinical or inapparent infections in experimental design and interpretation.

Diagnosis of Fasciola hepatica infections in sheep by an enzyme-linked immunosorbent assay.

An enzyme-linked immunosorbent assay (ELISA) was evaluated for diagnosis of Fasciola hepatica infections in sheep maintained under isolation and drylot conditions. Sheep were exposed to various numbers (100 to 500) of metacercariae, and blood was collected for assay at regular intervals thereafter. The ELISA values of controls were low and varied little. Although the ELISA detected antibodies to the flukes as early as postinoculation week (PIW) 2, ELISA values suggested as diagnostic (1.75 times control values) did not occur until PIW 6 to 8. Positive diagnosis of the infections by fecal examination for fluke eggs was not established until after PIW 10. Results also indicated that ELISA values were generally not correlated with magnitude of infection, concurrent nematode infections, or husbandry practices.

Effects of infectious bursal disease on Marek's disease vaccination: suppression of antiviral immune response.

Studies were made to determine whether infectious bursal disease virus (IBDV) infection would affect the response of chickens to turkey herpesvirus (HVT) vaccination in the development and level of HVT viremia and virus-neutralizing (VN) antibodies to HVT. The HVT viremia in the vaccinated chickens was not affected by IBDV, whether IBDV was inoculated simultaneously with HVT vaccination at one day of age or whether it was inoculated 3 weeks postvaccination with HVT. However, VN antibody response to HVT was significantly suppressed (P less than 0.001) when vaccinated chickens were exposed to IBDV either at the time of vaccination or at 3 weeks postvaccination. Such immunosuppression by IBDV of VN antibody response to HVT vaccination may result in a reduced antiviral immunity against Marek's disease virus.