ABSTRACT
Objective To investigate the influence of the variations of an epidemic focus on hemorrhagic fever with renal syndrome (HFRS) so as to provide a basis for effective control of HFRS.Methods HFRS epidemic data from the rapid development of urbanization of Huangdao District and the general development of Jiaonan City were collected and analyzed retrospectively from 1979 to 2014.And the HFRS cases,incidences,host animals and Hantavirus surveillances were compared.Results The three epidemic peaks occurred from 1979 to 2014 in Huangdao District and Jiaonan City,they were in the mid-1980s (1983-1987),the late 1990s (1995-1999) and around 2012 (2010-2014),and 954,80,37 and 2 506,614,432 cases were reported,respectively,in Huangdao District and Jiaonan City.The three peak years were 1986,1999 and 2012.And the annual incidences of Huangdao District were 385.73/100 000,15.64/100 000 and 2.51/100 000,respectively.The annual incidences of Jiaonan City were 67.07/100 000,28.68/100 000 and 14.68/100 000,respectively.The three peaks obviously appeared double peaks [the autumn and winter (from Oct.to Dec.) and the spring (from Jan.to Feb.)] in Jiaonan City.And the first peaks in Huangdao District was in the autumn and winter (from Oct.to Dec.) and the spring (from Jan.to Feb.),the second and the third were only in the autumn and winter (from Oct.to Dec.).Eight kinds of host animals were detected in Jiaonan City from 2005 to 2014.They were house mouse [27.53％ (1 108/4 024)],brown rat [25.50％ (1 026/ 4 024)],striped field mouse [14.84％ (597/4 024)],black rat [10.74％ (432/4 024)],hamsters [11.01％ (443/4 024)],shrew [8.72％ (351/4 024)],back grain hamster [1.02％ (41/4 024)] and club rat [0.65％ (26/4 024)].Two kinds of host animals were detected in Huangdao District.They were house mouse [57.14％ (16/28)] and brown rat [42.86％ (12/28)].The capture rates in Jiaonan City were higher than those of Huangdao District.The capture rate in 2012 was 8.04％ (855/10 638) and the capture rates in Huangdao District were all lower than 0.84％.The total detection rate in Jiaonan City was 2.81％ (113/4 024).And there was no positive detection for ten years in Huangdao District.Conclusions HFRS epidemic intensities have receded gradually in Huangdao District and Jiaonan City.The epidemic in Huangdao District obviously presents a low epidemic condition after the first peak.The few kinds and low densities of host animals are resulting in the sustainable condition.The evolution of epidemic patterns of HFRS is related to the change of epidemic sources by the differences in urbanization between the two places.
ABSTRACT
Objective To understand the ecological developmental characteristics of rats in the epidemic areas of hemorrhagic fever with renal syndrome (HFRS) so as to provide a basis for effective control of HFRS.Methods Based on the China National Disease Surveillance Reporting and Management System,data of HFRS cases from 2010 to 2014 were collected and analyzed by retrospective analysis.Meanwhile surveillance data of rats were collected and the capture rates in different seasons,genders and districts were also analyzed.Results Totally 51,92,129,85 and 71 cases of HFRS were reported from 2010 to 2014.Most HFRS cases occurred from October to November which were 43,59,78,37 and 37,respectively.Totally 2902 rats were captured from 2010 to 2014.The five-year average capture rate was 4.87％ (2902/59610).The highest capture rate was 6.94％ (910/13107) in the third quarter and the outdoor capture rate (5.80％,1681/28987) was higher than that of indoor(3.99％,1221/30623,x2 =324.35,P ＜ 0.05).More male rats were captured than female rats and the overall proportion was 62.82％ (348/554) and 37.18％ (206/554),respectively.The outdoor rats were mainly Apodemus agrarius (556),Cricetulus triton (432),Rattus noruegicus (217),Mus musculus (211) and Sorex araneus (139),and the indoor rats were mainly Mus musculus (514),Rattus noruegicus (469) and Sorex araneus (181).The black rat disappeared and White-bellied rat appeared.Conclusions The rat density keeps higher all year round and the type of rats has become increasingly complex.Mixed living of indoor and outdoor rats increased the infection probability of different types of Hantavirus,which has an immediate impact on the spreading pattern of HFRS.