Scanning electron microscopy of the egg of Mansonia dives (Diptera: Culicidae).

The egg of Mansonia dives (Schiner) is described by means of scanning electron micrographs and compared with other species described in previous studies. The egg of Ma. dives differs from those of Ma. uniformis (Theobald), Ma. indiana (Edwards), Ma. annulifera (Theobald), Ma. annulata (Leicester), and Ma. bonneae (Edwards) in that it has a tuberculated anterior cup. A key for identification of the eggs of the six Mansonia species, based on electron microscopy, is presented.

A clinical study on trichinosis in Changwat Phayao, Thailand.

An epidemic of trichinosis occurred in Northern Thailand. The source meat was a 150 kg hilltribe pig. A clinical investigation was conducted using indirect IgG ELISA as a criteria for diagnosis. 52 suspected cases who had eaten the trichinous pork and developed relevant symptoms were hospitalized. 49 of them gave positive ELISA within 64 days after infection. The most common clinical features were myalgia (100%), fever (93.88%) and facial edema (87.71%). Diarrhea was found in approximately one half of the patients (55.10%). Skin rashes of various types were unexpectedly high (40.82%).

Persistence of IgG, IgM, and IgE antibodies in human trichinosis.

An enzyme-linked immunosorbent assay (ELISA) was used to detect serum IgG, IgM, and IgE antibodies against Trichinella spirals s. str. following an outbreak of human trichinosis in 1989 in Chiang Rai Province, Thailand, for two years and seven months in order to observe diagnostic sensitivity of ELISA as well as the persistence of antibodies. It was found that the sensitivity of IgG-ELISA, as determined from biopsy-positive cases, reached 100% on the 50th day of infection. For IgM-ELISA, peak sensitivity was 93.33% at the 57th and IgE-ELISA 100% at the 85th day of infection. Two years and seven months after infection, the diagnostic sensitivity of IgG-ELISA was 88.24%, and that of IgE-ELISA was 47.06%, while the sensitivity of IgM-ELISA was only 11.76%. It was suggested from the data that IgM-ELISA is a helpful indicator of infection within three years. Other two groups of trichinosis cases, i.e., high-titer and seroconversion cases, were also studied. Antibody response curves were constructed from mean ELISA values from each group. It was revealed that all curves were similar in shape, independent of the group studied. The only exception was IgG-antibody response in the high-titer group, which showed the highest antibody level at the first collection of blood samples, i.e., 23 days after infection.

The value of enzyme-linked immunosorbent assay (ELISA) for diagnosis of human trichinosis.

Sera were collected from proven cases of trichinosis and other helminthic infections and examined for IgG and IgM antibodies by an enzyme-linked immunosorbent assay (ELISA). IgG-ELISA was positive in 68.75, 100, and 100% of cases on 23rd, 50th, 57th day of infection while IgM-ELISA was positive in 12.50, 85.71, 93.33% respectively. In the group with parasitic infections other than trichinosis 20.93% were positive by IgG-ELISA and strong cross-reactivity was prominent with intestinal capillariasis. With IgM-ELISA, positivity in the group with other parasitic infections was 9.30%. It was suggested that sera should be examined not before 1 month after infection to achieve maximum sensitivity for serodiagnosis of human trichinosis.