Cystic echinococcosis in semi-nomadic pastoral communities in north-west China.

In order to determine the prevalence of human cystic echinococcosis (CE) in semi-nomadic traditional pastoralist groups in north-west China, 2 large community studies were undertaken in Altai and Tacheng Prefectures in 1990/91 and 1995/96, respectively. The Kekergash community (Altai) comprised mainly ethnic Kazakhs, whereas the Narenhebuke community (Tacheng) comprised mainly Mongolians. Populations were screened for CE by abdominal ultrasound scan (US) and serological tests. The total prevalence of confirmed human CE was higher in Narenhebuke (2.7%, 49/1844) than in Kekergash (0.9%, 17/1861; P < 0.01). Within each community there was no significant difference of CE prevalence between the Kazakh and Mongolian groups, although Han Chinese exhibited twice the rate of CE (4.9%) in Narenhebuke compared to the dominant Mongolian population. For each community, human CE prevalence increased with age and there was a greater risk associated with the practice of home slaughter of livestock. Dogs were screened for Echinococcus granulosus infection and re-infection levels using a highly specific coproantigen test. The proportion of dogs with positive coproantigen tests was significantly higher in Narenhebuke (36.0%, 50/139) compared to Kekergash (17.8%, 16/90). In Narenhebuke the re-infection levels of dogs, as determined by coproantigen positivity, were higher in the winter quarters (49.4%, 39/79) compared to the summer quarters (18.3%, 11/60; P < 0.01). Furthermore, coproantigen re-test positivity was 25% at 3 months and 29.2% at 7 months. Highest dog coproantigen positivity was obtained over the winter period.

[The excitatory effects of histamine on cerebellar cortical Purkinje cells in the rat].

The effects of histamine on Purkinje cells (PCs) in lobule X of cerebellar cortex were investigated in rat cerebellar slices. Histamine elicited PCs' responses predominately excitatory (94.4%, 51/54), only few inhibitory (5.6%, 3/54). The excitatory response could not be abolished by perfusing the slices with low Ca2+/high Mg2+ medium. The excitatory response of PCs to histamine could be blocked by histamine H2 receptor antagonist ranitidine, but not by H1 receptor antagonist triprolidine readily. These results suggest that histamine exerts an excitatory effect on the PCs via H2 receptors. Presumably, hypothalamo-cerebellar histaminergic fibers participate in the regulation of somatic and non-somatic functions of the cerebellum.

[The cohort study on HFRSV antibody variation in normal population of an epidemic area].

We randomly selected 2,796 persons in an epidemic area of HFRS in Anhui province for serological study from April to December in 1988. The results showed that the antibody prevalence rates were 7.3%, 10% and 14% respectively in April, September and December. Their GMT were 1.30, 1.42 and 1.73 respectively. Indoor rodent density and HFRSV carrying rate were respectively 7.8%, 6.4% in April, 9.4%, 8.8% in September, and 7.5%, 8.2% in December. Outdoor rodent density and HFRSV carrying rate were respectively 10.0%, 6.8% in April, 29.5%, 12.2% in September, and 10.8%, 11.0% in December. The positive seroconversion rate was 6.0% and negative seroconversion rate was 18.0%. The ratio of clinical infection to subclinical infection was 1:26. It is conclude that subclinical infection is dominant in HFRS infection, outdoor rodent density and their HFRSV carrying rate are the main factors for the infection in this HFRS endemic area.