RESUMO
Leptospirosis has long been a sporadic zoonosis in Liping County.This study aims to explore the risk factors of leptospirosis infection in general population,and the role rodents play in transmission by an expanded investigation of two deceased cases.Serology survey and demographic investigation were carried out among the general population of two epidemic areas where two deseased cases had been reported,and one extended area where no leptospirosis cases had been diagnosed.Local rodents' kidney samples were collected for Leptospira isolation.In total 44 people (23.4％) tested positive by microscopic agglutination test (MAT) for four strains of Leptospira.Seropositive rate of the extended area was significantly higher (53.3 ％,24/45) than epidemic area (14.0％,20/143).Positive rate increased with age.Other factors such as occupation,gender showed no significance.The proportion of Apodemus agrarius in the captured rodents and the total germ-carrying rates showed no significant difference in two areas.Long-term rodent carrier surveillance is critical to provide valuable information and locate high risk areas,facilitating prophylactic measures.Vaccination was recommended in high risk areas if economical feasibility and demand were proved.
RESUMO
<p><b>OBJECTIVE</b>To understand the incidence rates of both typhoid fever and paratyphoid fever in the high prevalent areas of Guizhou province so as to provide evidence for the development of programs on comprehensive intervention and effectiveness evaluation.</p><p><b>METHODS</b>Six townships in Pingba county were selected as intervention areas while six townships in Kaiyang county were taken as control. All hospitals and clinics were classified into A, B and C types according to its level and the capacity of the blood culture. Surveillance on typhoid and paratyphoid fever was conducted based on all population and all hospitals, clinics and county CDCs among the patients with unknown fever.</p><p><b>RESULTS</b>In the surveillance area in those two counties, there were 12 944 blood samples from patients with unknown fever which have been tested and cultured. Among them, 200 strains of Salmonella including 16 typhoid strains, 184 paratyphoid A strains were identified, with the total positive rate as 1.55%. The positive rate before the intervention program was higher than the after. The detection rate was 1.91% in the type A hospitals. 39 strains of Salmonella have been cultured from 2039 samples which accounting for 19.50% (39/200) of the total strains. 4315 blood samples were cultured at the 'Class B' sites which isolated 82 strains of Salmonella, accounting for 41.00% (82/200), with a detection rate as 1.90%. 6590 samples were cultured at the 'Class C' sites, which identified 79 strains of Salmonella, accounting for 39.50% (79/200), with a detection rate as 1.20%. The detection rate was much higher before the use of antibiotics than after using them (P < 0.05). The annual peak time of positive detection was in spring and fall. The outbreaks or epidemics often appeared in the same places, with farmers, students as the high-risk populations. Symptoms of both typhoid and paratyphoid fever were not typical.</p><p><b>CONCLUSION</b>Typhoid and paratyphoid monitoring programs which covered primary health care institutions in the high incidence area seemed to be effective in reflecting the pictures as well as the burden of both typhoid and paratyphoid.</p>