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Rabies is an acute human and animal infectious disease mainly caused by rabies virus infection of the central nervous system. Human rabies is usually transmitted by the bite of an animal carrying the rabies virus. There is no treatment method yet, and the case fatality rate is almost 100% (1-2). Since 1998, the incidence of rabies in China began to slowly increase, and after reaching the peak in 2007, the incidence generally decreased (3). Hunan Province had one of the highest incidences of rabies in China (4). In order to assess the epidemic situation and epidemic factors and provide a scientific basis for formulating effective prevention and control measures, the characteristics and trends of rabies in Hunan Province in 2020 were analyzed.
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A total of 59 rabies cases were reported in Hunan Province in 2020, an increase of 4 cases from 2019, and the reported incidence was 0.09/100,000 population, including 24 confirmed laboratory cases. In 2020, a total of 32 cases were sampled and tested in the province. The case detection rate was 54.24% (32/59), of which 21 cases were positive and the positive rate was 65.63% (21/32). In 2020, 25 counties (cities, districts) reported rabies cases. All 59 cases reported died in 2020.
Of the 59 cases, 51 (86.44%) did not treat wounds by themselves or attend medical institutions for wound treatment after exposure and did not receive vaccination or use RIG. Only eight went to medical institutions for wound treatment, three had their wounds squeezed and bled, five had their wounds cleaned and disinfected, and only four cases received RIG but not the complete rabies vaccine (Table 1).
Contents Number of cases Constituent ratio (%) Wound site Hand and combined injury of hand 24 40.68 Lower limb below knee 12 20.34 Arm 6 10.17 Head and face combined injury 5 8.47 Lower limbs above knee 6 10.17 Unknown 6 10.17 Exposure mode Bite 42 71.19 Scratch 7 11.86 Others 10 16.95 Exposure level Degree I 2 3.39 Degree II 14 23.73 Degree III 43 72.88 Wounding animals Dogs 56 94.92 Cats 2 3.39 Others 1 1.69 Category of wounding dog Self-raised 22 39.29 Neighbor raised 17 30.36 Stray dog 17 30.36 Table 1. Characteristics of exposure history and post-exposure prophylaxis, Hunan Province, 2020.
In 2020, a total of 11 incidents of multi-victims bitten by a single dog (i.e., one dog injuring three or more people) were detected. Overall, 8 of the 11 incidents occurred in rural areas and 3 in urban areas. Almost all months had such incidents reported except January, April, July, and December, and there were 2 incidents in March, August, and October. The incidents took place in 5 cities, including Yueyang (3 incidents), Yongzhou (3 incidents), Loudi (2 incidents), Changsha (2 incidents), and Changde (1 incident).
A total of 11 dogs were involved in the 11 incidents, of which 7 were stray dogs (63.64%) and 4 were domestic dogs; none of the domestic dogs had a history of animal rabies vaccination. Brain specimens of 10 dogs were collected for DFA detection, and the detection results were 100% positive.
A total of 67 persons were exposed in 11 incidents, with one incident involving as high as 10 persons, and the rest less than 10. Among all the exposed persons, 61 were classified as level III and 6 as level II. All victims were given standardized PEP according to the national guidelines and none developed rabies.
A total of 603,261 outpatients were reported in rabies PEP clinics in Hunan, accounting for 0.86% of the total population of Hunan (70.5 million). Of all reported outpatients, the male-female sex ratio was 1.04∶1; exposure grades I, II, and III accounted for 3.46%, 49.73%, and 46.81%, respectively. Injured animals were mainly dogs (447,316, 74.21%). Only 83,418 (13.84%) of attacking animals had a clear immune history.
From the surveillance data reported in Hunan, 44.96% of all outpatients treated the wounds in time after exposure; 87.45% received wound treatment in various preventive clinics; 96.84% were fully vaccinated after exposure; and 139,414 exposures received antiserum or immunoglobulin, accounting for 49.41% (139,414/282,173) of all graded exposure.
Rabies host animal surveillance data were reported in 14 sentinel cities in Hunan Province. According to the data reported, the density of dogs varied greatly in Hunan Province, with a range of 1.48–8.43/100 people and an average of 4.51/100 people. The immunization rates of the dogs also varied greatly among different cities, ranging from 11.82% to 68.24%, with an average of 30.98%.
In 2020, 554 dogs’ brain tissue was collected in Hunan Province, and 20 dogs tested positive with a positivity rate of 3.61%. The positive detection of different kinds of dogs is shown in Table 2.
Source of dogs Number of dogs Number of positive cases Positive rate (%) Generally hurt dogs* 265 2 0.75 Dogs in epidemic source areas† 258 0 0.00 Hurt multiple dogs§ 31 18 58.06 Total 554 20 3.61 * A dog that only hurts one person.
† The dogs raised in areas within 5 kilometers of the location of the human rabies case.
§ Three or more people were injured by one dog.Table 2. Results of dog rabies virus detection from different sources in Hunan Province in 2020.
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