我国人与犬、猫共患病防控存在的主要问题与对策建议

随着社会经济的发展、城市化进程的加速及人们生活水平的不断提高,越来越多的宠物走进了人们的家庭,在人类社会生活中发挥了积极作用。但同时,宠物也是人兽共患病的重要传染源和传播媒介。与人类关系最为密切的犬、猫在人兽共患病的防控中具有重要的意义。在已报道的200多种主要的人兽共患病中,与宠物犬、猫有直接或间接关系的有70余种。随着宠物犬猫数量的大幅攀升和宠物业的飞速发展,我国人与犬猫共患病可能会出现逐步高发的趋势,疫病防控工作面临着许多问题。为了完善宠物管理制度,建立有效的防疫监督体系,对人与犬猫共患病实行有效的防控,本文就完善法律法规、形成综合管理机制,加强卫生监督、强化无害化处理、培养专业人才以及广泛开展宣传教育等6个方面提出了相关建议。     

感染人类的宠物螨病

螨病是一种由螨虫引起的非季节性、瘙痒性宠物皮肤病。此病可以发生于多种哺乳动物,尤其是家养宠物,偶尔会传染给与之接触的人类,并引起瘙痒和自限性皮炎。犬猫做为人类最主要的宠物,其皮肤可以藏匿几种螨虫,主要包括犬疥螨、猫背肛螨和姬螯螨,这些螨虫都是具有引发人兽共患病的潜在能力。与宠物密切接触的人一旦出现可疑皮肤病应该警惕螨病的存在。犬猫螨病的诊断应该基于直接发现螨虫,分析其形态和获取动物宿主临床症状。了解这些螨病的发病特点并做好适当预防是控制此类人兽共患病的关键。     

宠物狂犬病及其防控

本文对狂犬病在犬、猫等宠物中的流行情况;宠物狂犬病及其危害;宠物狂犬病的预防及国外宠物狂犬病的防控经验等进行了综述,为保证宠物和人类健康、有效防控宠物狂犬病提供参考。     

几种实验动物重要疫病及其防控研究

本文结合作者科研工作实际和相关文献资料,对犬、猫、猴等实验动物犬瘟热、犬细小病毒病、猫瘟热、布病、钩体病及弓形虫病等重要疫病及其防控研究进行了概述.     

对24例宠物临诊病例检测未发现新型冠状病毒（SARS-CoV-2）核酸阳性

2019新型冠状病毒(SARS-CoV-2)是一种在人体中新发现的冠状病毒,来源于野生动物。SARS-CoV-2属于冠状病毒科β冠状病毒属,而感染宠物犬猫类的冠状病毒主要来自α冠状病毒属。SARS-CoV-2是否感染犬、猫等宠物是当前抗击新冠肺炎疫情的重要公共卫生问题,也是大众关切的热点问题之一。本研究试图通过对有明晰腹泻和呼吸道症状的宠物犬和猫进行病原学检测,来阐明SARS-CoV-2是否感染宠物的科学问题,探究腹泻和呼吸症状宠物感染的普遍病因。本研究采用SARS-CoV-2的荧光定量PCR试剂和已经建立的诊断方法,对SARSCoV-2流行期间北京地区有腹泻和呼吸道症状的(特别是有发烧、严重咳嗽症状)临床宠物猫病例(20例)和宠物犬病例(4例)采集咽拭子,并进行SARS-CoV-2核酸荧光定量PCR检测和犬瘟热病毒(Canine distemper virus,CDV)、犬细小病毒(Canine parvovirus,CPV)、犬腺病毒Ⅱ型(Canine adenoviru-2,CAV-2)、犬副流感病毒(Canine parainfluenza virus,CPIV)、猫疱疹病毒I型(Feline herpesvirus-1,FHV-1)及猫杯状病毒(Feline calicivirus,FCV)、支原体(Mycoplasma,MY)及衣原体(Chlamydophila,CPS)等病原的检测。结果表明,所有样本SARS-CoV-2均为阴性,但分别存在其它病原感染。     

宠物犬和猫流感病毒感染

近十年来犬和猫流感病毒感染报道迅速增多,不仅威胁到犬和猫的健康,也对公共卫生造成了影响。自2004年首次发生H3N8亚型流感病毒感染赛犬事件以来,犬流感一直在美国的赛犬和宠物犬中流行。在韩国和我国南方的犬群中出现了因H3N2亚型禽流感感染引起的肺炎病例。亚洲和欧洲均报道了猫H5N1亚型高致病性禽流感致死性感染病例,还通过实验研究发现H5N1亚型流感病毒可在猫与猫之间水平传播。这些现象预示着流感病毒进一步获得了感染哺乳动物的能力,其公共卫生意义需引起关注。为此,本文对犬和猫流感病毒感染的流行病学、临床症状、发病机制、诊断和防控措施进行了综述。     

宠物结核病的危害及其防治

随着生活水平的提高,宠物的数量和种类增长迅速。结核病是目前病死人数最多的人兽共患病,犬、猫和鸟类都能感染发病,对人类,尤其是免疫抑制人群威胁很大。监测和防治宠物结核病对人类结核根除计划具有重要意义。     

宠物会引发人类传染病吗?

Q:宠物会引发人类传染病,你知道吗?A:动物是各种病原体的储存库,绝大多数动物是人畜共患病的传染源和贮存宿主。人们身边的宠物能携带某些疾病的病原,它自己不生病,但能将多种疾病传播给人类。随着人们生活水平的提高及人口老龄化,豢养宠物已成为一种生活上的享受和乐趣。特别是豢养犬、猫,各种禽类、鸟类等很多见。有些人与宠物同居一堂,餐具不分,甚至带着宠物同床睡觉。这说明宠物已直接进入家庭生活,对人类健康造成的隐患也越来越多。     

猫与人畜共患病

猫是多种人畜共患病的传播者,现介绍以下几种病供参阅。弓形虫病由弓形虫属、刚地弓形虫引起的一种原虫病。本病是世界性分布,具有广泛的自然疫源性。人感染后多呈隐性感染,免疫力低下的个体可出现严重症状。本病临床表现复杂,主要侵犯眼、脑和淋巴结等部位。猫和某些猫科动物为弓形虫病的主要传染源。传播途径可分为先天性和获得性两种。先天性为胎儿在子宫内从母体获得感染,妇女妊娠期感染本病后,可通过胎盘感染胎儿,胎儿也可摄入羊水而感染。获得性感染     

宠物对人类健康的潜在威胁

宠物是多种人兽共患病病原的宿主和传播媒介,由于传统宠物、另类宠物和进口宠物的增多,宠物来源的感染性疾病有了高发的趋势。本文总结了狗、猫、啮齿类、鸟类、鱼和爬行类宠物可能带有的人兽共患病病原,引发的疾病和传播途径。并概括了防控宠物源性感染性疾病的防控措施。     

Prevalence of Toxoplasma gondii in stray cats of Gyeonggi-do, Korea

Toxoplasma gondii is an obligate intracellular zoonotic protozoan with a worldwide distribution. It infects humans as well as a broad spectrum of vertebrate hosts. Cats and wild felidae play crucial roles in the epidemiology of toxoplasmosis. This study was performed to survey the prevalence of T. gondii infection among stray cats in the Gyeonggi-do, Republic of Korea. A total of 174 stray cat blood samples were collected from Gwacheon-si (n=20), Bucheon-si (82), and Yangju-si (72). Positive sera for T. gondii were identified in 14 samples (8.1%) exclusively via the latex agglutination test, 28 (16.1%) via ELISA, and 23 (13.2%) via PCR analysis. The overall infection rate of female stray cats (29.2%) presented as higher than that of male cats (24.0%). This study suggests that T. gondii is widespread in the stray cat population of Gyeonggi-do, Korea. It is urgently needed to control urban stray cat population and to reduce the risk of zoonotic transmission of toxoplasmosis to other animal hosts and humans.     

Prevalence of Toxoplasma gondii antibodies and DNA in dogs in Shanghai, China

The aim of this study was to estimate the prevalence of Toxoplasma gondii infection in dogs in Shanghai, China. A total of 1,736 sera (1,178 from the city center and 558 from the outskirts) was collected from healthy dogs and tested for T. gondii infection by indirect hemagglutination; 56 sera (3.2%) were considered positive, with titers > 1∶64. The seroprevalence in dogs from the outskirts of the city (town dogs, 6.0%; countryside dogs, 9.8%) was significantly higher (P > 0.05) than that in city center dogs (1.3%). The age of the dog has an apparent association with T. gondii infection; that is, the seroprevalence ranged from 1.9% (in dogs ≤ 1 year old) to 3.6% (in dogs > 5 years old). There was no significant difference in gender (P ≥ 0.05), that is, 1.4% versus 1.1% for male and female dogs in the city center, 6.2% versus 5.9% in town dogs, and 8.4% versus 11.5% in country dogs, respectively. These results suggest that T. gondii infections are common in dogs from the city center and outskirts of Shanghai, but the T. gondii seroprevalence in dogs is considerably lower than in other regions in PR China. The presence of T. gondii DNA was investigated by nested PCR on 110 blood samples from city center dogs, but no positive samples were found, which may suggest that there were no acute infections of T. gondii in the city center samples. Our results indicate that the control and treatment of toxoplasmosis in Shanghai has been effective. However, it is still essential to further implement integrated strategies to prevent and control T. gondii infection in dogs in both the city center and the outskirts.     

Seroprevalence and risk factors for Toxoplasma gondii infection on pig farms in central China

Toxoplasma gondii is a protozoan parasite that causes severe diseases in mammals, including humans, around the world. In China, pork is the main meat source; accordingly, T. gondii in pigs is considered an important source for human toxoplasmosis. Understanding the epidemiology of toxoplasmosis in pig farms is thus important for control of the disease in humans. The purpose of the present study was to investigate the epizootiology of T. gondii infections in pig farms in central China by assessing the seroprevalence and risk factors of this disease. In the present study, 3,558 sera samples were collected from pigs in 37 large-scale pig farms in this region and tested by AG-ELISA. The total seroprevalence was 24.5%, with the greatest prevalence in breeding pigs. The risk factors for toxoplasmosis suggest that high frequency of the contact of pigs with cats (P ≤ 0.01; IC 95%), high density of pig breeding (P ≤ 0.01; IC 95%), the presence of mosquitoes and flies (P ≤ 0.01; IC 95%), semi-patency pens (P ≤ 0.05; IC 95%), and low frequency of scavenging (P ≤ 0.01; IC 95%) were all associated with seroprevalence. In addition, the use of sulfonamides (P ≤ 0.01; IC 95%) significantly decreased seroprevalence. This is the first report of anti- T. gondii antibodies in pigs on large-scale pig farms in central China. The findings will provide useful information for designing control strategies of toxoplasmasis in pig farms.     

Development of a PCR-enzyme immunoassay oligoprobe detection method for Toxoplasma gondii oocysts, incorporating PCR controls

Infections caused by Toxoplasma gondii are widely prevalent in animals and humans throughout the world. In the United States, an estimated 23% of adolescents and adults have laboratory evidence of T. gondii infection. T. gondii has been identified as a major opportunistic pathogen in immunocompromised individuals, in whom it can cause life-threatening disease. Water contaminated with feces from domestic cats or other felids may be an important source of human exposure to T. gondii oocysts. Because of the lack of information regarding the prevalence of T. gondii in surface waters, there is a clear need for a rapid, sensitive method to detect T. gondii from water. Currently available animal models and cell culture methods are time-consuming, expensive, and labor-intensive, requiring days or weeks for results to be obtained. Detection of T. gondii nucleic acid by PCR has become the preferred method. We have developed a PCR amplification and detection method for T. gondii oocyst nucleic acid that incorporates the use of hot-start amplification to reduce nonspecific primer annealing, uracil-N-glycosylase to prevent false-positive results due to carryover contamination, an internal standard control to identify false-negative results due to inadequate removal of sample inhibition, and PCR product oligoprobe confirmation using a nonradioactive DNA hybridization immunoassay. This method can provide positive, confirmed results in less than 1 day. Fewer than 50 oocysts can be detected following recovery of oocyst DNA. Development of a T. gondii oocyst PCR detection method will provide a useful technique to estimate the levels of T. gondii oocysts present in surface waters.     

High prevalence of viable Toxoplasma gondii infection in market weight pigs from a farm in Massachusetts

The ingestion of uncooked infected meat is considered important in the epidemiology of Toxoplasma gondii infection in humans and little is known of the prevalence of viable T. gondii in meat used for human consumption in the United States. In the present study, viable T. gondii was isolated from 51 out of 55 pigs destined for human consumption. Hearts and tongues (500 g) from fifty-five 6-mo-old pigs from a farm in Massachusetts were bioassayed for T. gondii by feeding them to T. gondii-free cats. Feces of these cats were examined for shedding of T. gondii oocysts. Fifty-one of 55 cats fed pig tissues each shed 25-810 million T. gondii oocysts in their feces. Two of these cats consumed tissues of pigs that were shown to be seronegative with the Sabin-Feldman dye test, the modified agglutination test, and the Western blot. Results indicate that until examination of meat for T. gondii infection is implemented in slaughterhouses, all meat should be cooked according to industry guidelines before human consumption.     

Evaluation of a Direct Agglutination Test for Detection of Antibodies Against Toxoplasma gondii in Cat,Pig and Sheep Sera

The protozoan parasite Toxoplasma gondii is the causative agent of the zoonosis toxoplasmosis. In sheep and goats, it is one of the most prevalent causes of infectious abortion. Also in pregnant women, a primary infection can result in miscarriage. Humans acquire the infection either by ingestion of oocysts excreted by cats, the definitive host of the parasite, or by eating raw or undercooked meat from latently infected animals (Dubey & Beattie 1988). In Sweden, toxoplasmosis is a notifiable disease, and cases of clinical disease in humans as well as animals must be reported. In both veterinary and human medicine serological assays based on detecting the humoral antibody response of the host against the parasite are used as diagnostic tools. So far, solid phase assays, such as the indirect fluorescent antibody test (IFAT) and the enzyme-linked immunosorbent assay (ELISA), have been widely used to diagnose T. gondii infection in many species including cats, pigs and sheep (Dubey & Beattie 1988). However, both IFAT and ELISA require appropriate anti-species specific immunoglobulins (Ig) that must be carefully evaluated for each species prior to use. This makes these assays complicated and time consuming. Consequently, alternative, simpler methods that do not require specific antisera would be of great value. The direct agglutination test (DA), which is based on the principle that formalin-treated organisms agglutinate in the presence of specific IgG antibodies, is such an assay (Fulton & Turk 1959). The DA-test is widely used in human medicine as a screening test for T gondii infection but it has not yet been thoroughly evaluated for use in veterinary medicine (Uggla & Buxton 1990).     

Toxoplasma gondii: from animals to humans

Toxoplasmosis is one of the more common parasitic zoonoses world-wide. Its causative agent, Toxoplasma gondii, is a facultatively heteroxenous, polyxenous protozoon that has developed several potential routes of transmission within and between different host species. If first contracted during pregnancy, T. gondii may be transmitted vertically by tachyzoites that are passed to the foetus via the placenta. Horizontal transmission of T. gondii may involve three life-cycle stages, i.e. ingesting infectious oocysts from the environment or ingesting tissue cysts or tachyzoites which are contained in meat or primary offal (viscera) of many different animals. Transmission may also occur via tachyzoites contained in blood products, tissue transplants, or unpasteurised milk. However, it is not known which of these routes is more important epidemiologically. In the past, the consumption of raw or undercooked meat, in particular of pigs and sheep, has been regarded as a major route of transmission to humans. However, recent studies showed that the prevalence of T. gondii in meat-producing animals decreased considerably over the past 20 years in areas with intensive farm management. For example, in several countries of the European Union prevalences of T. gondii in fattening pigs are now <1%. Considering these data it is unlikely that pork is still a major source of infection for humans in these countries. However, it is likely that the major routes of transmission are different in human populations with differences in culture and eating habits. In the Americas, recent outbreaks of acute toxoplasmosis in humans have been associated with oocyst contamination of the environment. Therefore, future epidemiological studies on T. gondii infections should consider the role of oocysts as potential sources of infection for humans, and methods to monitor these are currently being developed. This review presents recent epidemiological data on T. gondii, hypotheses on the major routes of transmission to humans in different populations, and preventive measures that may reduce the risk of contracting a primary infection during pregnancy.     

Diverse and atypical genotypes identified in Toxoplasma gondii from dogs in São Paulo, Brazil

The prevalence of Toxoplasma gondii in 118 unwanted dogs from S?o Paulo City, S?o Paulo State, Brazil, was determined. Antibodies to T. gondii were assayed by the modified agglutination test and found in 42 (35.8%) dogs, with titers of 1:20 in 10, 1:40 in 6, 1:80 in 5, 1:160 in 5, 1:320 in 6, 1:640 in 7, and 1:1,280 or higher in 3. Hearts and brains of 36 seropositive dogs were bioassayed in mice, or cats, or both. Tissues from 20 seropositive dogs were fed to 20 T. gondii-free cats. Feces of cats were examined for oocysts. Toxoplasma gondii was isolated from 15 dogs by a bioassay in mice, from the brain alone of 1, from the heart alone of 4, and from both brains and hearts of 10. All infected mice from 5 of 15 isolates died of toxoplasmosis during primary infection. Four additional isolates were obtained by bioassay in cats. Genotyping of these 19 T. gondii isolates using polymorphisms at 10 nuclear markers including SAG1, SAG2, SAG3, BTUB, GRA6, c22-8, c29-2, L358, PK1, and a new SAG2 (an apicoplast marker Apico) revealed 12 genotypes. One isolate had Type III alleles at all 11 loci, and the remaining 18 isolates contained a combination of different alleles and were divided into 11 genotypes. The absence of Type II in Brazil was confirmed. The result supports previous findings that T. gondii population genetics is highly diverse in Brazil.     

Low virulence of oocysts of Czech Toxoplasma gondii isolates on the basis of biological and genetic characteristics

The virulence of the oocysts of 7 Czech Toxoplasma gondii isolates was tested. The oocysts were obtained by experimental infection of cats with the tissue cysts of T. gondii isolates from dogs, cats, and rabbits. The cats shed the oocysts in feces, with prepatent periods of 3-5 days postinfection (PI); the patent period was 7-18 days. The number of oocysts shed varied between 0.94 million and 47 million, with 0.66 million-39 million oocysts found in the daily samples of excrement. The cats ceased oocyst production at 11-22 days PI. Sporulated oocysts were used to prepare infective doses of 1 to 10(5) oocysts for oral infection of 10 mice. Deoxyribonucleic acid isolated from 4 T. gondii isolates was used in polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP) for amplification of the ROP1 gene and restriction of the product of amplification by restriction endonuclease DdeI. On the basis of their biological characteristics, all 7 isolates belonged to the group of "avirulent" strains. In the PCR-RFLP tests, 2 isolates, K9 and K19, showed an "avirulent" strain pattern.     

Toxoplasma gondii infections in cats from Paraná, Brazil: seroprevalence, tissue distribution, and biologic and genetic characterization of isolates

Cats are important in the epidemiology of Toxoplasma gondii because they are the only hosts that can excrete environmentally resistant oocysts. The prevalence of T. gondii was determined in 58 domestic cats from 51 homes from Santa Isabel do Ivai, Parana State, Brazil where a water-associated outbreak of acute toxoplasmosis had occurred in humans. Antibodies to T. gondii were found with the modified agglutination test in 49 of 58 (84.4%) cats at a serum dilution of 1:20. Tissues (brain, heart, and skeletal muscle) of 54 of these cats were bioassayed in T. gondii-free, laboratory-reared cats; T. gondii oocysts were excreted by 33 cats that were fed feline tissues. Brains from these 54 cats were bioassayed in mice; T. gondii was isolated from 7. Skeletal muscles and hearts of 15 cats were also bioassayed in mice; T. gondii was isolated from skeletal muscles of 9 and hearts of 13. The results indicate that T. gondii localizes in muscle tissue more than the brains of cats. In total there were 37 T. gondii isolates from 54 cats. Most isolates of T. gondii were virulent for mice. Genotyping of the 37 isolates of T. gondii, using the SAG2 locus, revealed that 15 isolates were type I and 22 were type III. The absence of type II genotype in cats in this study is consistent with the previous studies on T. gondii isolates from Brazil and is noteworthy because most T. gondii isolates from the United States are type II. These findings support the view that Brazilian and North American T. gondii isolates are genetically distinct. This is the first report of genotyping of T. gondii isolates from the domestic cat.