Echinococcus granulosus in dogs and sheep in central Utah, 1971-1976

During 1971 to 1976, a survey was conducted to determine the prevalence of Echinococcus granulosus infection among dogs and sheep in central Utah. For each year, the number of dogs positive for adult tapeworms of the total number examined and the percentage infected were: in 1971, 14 of 51 infected (27.4%); in 1972, 13 of 46 infected (28.3%); in 1973, 7 of 36 infected (19.4%); in 1974, 34 of 244 infected (13.9%); in 1975, 13 of 267 infected (4.9%); and in 1976, 14 of 195 infected (7.2%), or a 6-year total of 95 of 839 infected (av = 11.3%). For each year, the number of sheep positive with hydatid cysts of the total number examined and the percentage infected were: in 1971, 103 of 1,007 infected (10.2%); in 1972, 235 of 1,808 infected (13.0%); in 1973, 242 of 2,003 infected (12.1%); in 1974, 105 of 1,406 infected (7.5%); in 1975, 96 of 1,599 infected (6.0%); and in 1976, 96 of 1,171 infected (8.2%), or a 6-year total of 877 of 8,994 infected (av = 9.8%). These results represent a definite decline in numbers of infected animals and suggest that preventive and control measures advocated in central Utah are being implemented.     

Distribution of Brucella abortus in infected cattle

Experimentally and naturally infected cattle were examined bacteriologically to determine the anatomical distribution of specimens yielding Brucella abortus. In 91 experimentally infected pregnant cows, examined 3 to 4.5 months after conjunctival challenge during pregnancy, the most frequently infected specimen was the mammary (syn. supramammary) lymph node. All experimentally infected cows could be identified from cultures of the mammary, mandibular (syn. submaxillary), medial iliac, caudal superficial cervical (syn. prescapular) lymph nodes and uterine caruncles, cotyledons or foetal tissues. Forty-six naturally infected cows were examined and again the most frequently infected specimen was the mammary lymph node. All naturally infected cows could be identified from cultures of the mammary, parotid, mandibular and subiliac (syn. prefemoral) lymph nodes. The distribution of infected specimens was somewhat different in heifers. In 61 naturally infected heifers the most frequently infected specimen was the mandibular lymph node but 8 other specimens would have been required to enable identification of all infected heifers. Specimens from 3 infected bulls were cultured and 11 of the 12 specimens examined were infected in at least one of the bulls. The most frequently infected tissues were the mandibular, caudal superficial cervical, subiliac and scrotal lymph nodes. The results suggest which specimens should be selected for culture, particularly when only a limited amount of effort can be expended.     

Nested PCR on blood and milk for the detection of Mycobacterium avium subsp paratuberculosis DNA in clinical and subclinical bovine paratuberculosis

OBJECTIVE: To determine the potential of PCR on blood and milk to detect cattle infected with Mycobacterium avium subsp paratuberculosis. PROCEDURE: A nested PCR method probing for IS900 was developed and compared to ELISA serology in 11 clinically infected and 46 subclinically infected, lactating Holstein cows from a herd with confirmed paratuberculosis (Johne's disease). RESULTS: When compared to serum ELISA the nested blood- and milk PCRs were equal in identifying DNA from clinically infected animals. The PCR procedures also gave positive DNA results with some subclinically infected animals when these only gave suspicious or negative results in the ELISA test. Most clinically and subclinically infected animals were detected with milk PCR. CONCLUSION: Since there may well be a haematological phase in paratuberculosis, nested PCR testing of blood and milk samples shows potential to detect animals subclinically infected with M a paratuberculosis. More subclinically infected animals need to be tested and confirmed infected before estimates of sensitivity and specificity can be made.     

柑桔根系接触与黄龙病传播关系的研究

黄龙病是柑桔最严重的传染性病害,其病原菌在病株地上各部位和根部均有分布,主要通过病芽嫁接和柑桔木虱Diaphorina citri Kuwayama进行传播。本文研究了黄龙病通过柑桔根部传病的可能性,结果表明,将感染黄龙病的红皮山桔苗与健康沙糖桔苗直接合种在一起,3年后健苗均没有发病;但是将病苗、健苗的侧根表面切除、相互连接绑缚合种在一起6个月后发现,30株健苗中有1株感染了黄龙病,9个月后感染数达到9株,12个月后为11株,感染率达36.67%,说明病树、健树根系直接交叉生长并不能传播黄龙病,但通过病根嫁接、病健苗的根系生长融合在一起则可以导致病原的传播,即病根嫁接与病芽嫁接一样具备传播黄龙病的能力,而且传播效率较高。     

Effects of the dose of Ehrlichia phagocytophila on the severity of experimental infections in lambs

Twenty-one lambs were used to investigate whether their response to an infection with Ehrlichia phagocytophila was dose-dependent Four groups of four lambs were infected intravenously with a dilution in physiological saline of E phagocytophila-infected sheep blood containing either 1.3 x 10(5) infected cells, or approximately 43 infected cells, 4.3 infected cells, or 1.3 infected cells (mean values) and four lambs were left uninfected. The incubation period was significantly shorter in the lambs infected with the highest dose of E phagocytophila. However, the clinical and haematological changes observed, and the weekly weight gains of the lambs were independent of the dose of E phagocytophila. As little as one Ephagocytophila infected cell may be enough to transmit the infection.     

Critical tests of morantel-trichlorfon paste formulation against internal parasites of the horse

Critical tests were completed on six horses to evaluate the antiparasitic activity of a paste formulation mixture of morantel citrate and trichlorfon, administered intraorally at the dose rate of 6 mg morantel base kg-1 and trichlorfon at 30 mg kg-1. Aggregate average removals were: 78% for two horses infected with 2nd instar Gasterophilus intestinalis; 100% for one infected with 2nd instar G. nasalis; 96% for six infected with 3rd instar G. intestinalis; 100% for four infected with 3rd instar G. nasalis; 100% for five infected with Parascaris equorum; 100% for one infected with mature Oxyuris equi; 100% for five infected with Strongylus vulgaris; 72% for five infected with S. edentatus; and partial removal (25%) of Anoplocephala perfoliata infection from one infected animal. Pre- and post-treatment EPG and LPG data indicated a reduction of 97% of the mature small strongyle infections. Evidence of toxicosis was not observed in any of the horses.     

Responses of Fasciola hepatica infected sheep to various infection levels

The response to Fasciola hepatica was studied in sheep infected with 5, 30, 150 metacercariae. The animals were necropsied 12 weeks post-infection (p-i) for counting and measuring flukes. Cellular and humoral responses were detected by peripheral eosinophil count, peripheral blood lymphocyte proliferation with excretory-secretory products (FhESP) and ELISA. All sheep were infected at necropsy except one sheep which was infected with 5 metacercariae. Mean parasitic intensities were 40%, 44% and 27% of the infection dose in sheep infected with 5, 30, 150 metacercariae respectively. FhESP-specific lymphocyte responses of the 3 infected groups were significantly enhanced in weeks 3 and 4 p-i (p < 0.05). The kinetics of the specific humoral response were similar for the 3 infected groups but the antibody level was significantly lower in animals infected with 5 metacercariae than in the 2 other infected groups from week 5 p-i to week 12 p-i (p < 0.05). Peripheral eosinophil count was significantly enhanced (p < 0.05) in infected groups. The numbers of peripheral eosinophils were significantly different between the 3 infected groups in week 3, 4 and 6 p-i and were related to infection level. These results confirm that sheep are highly susceptible to F. hepatica infection, even when infection pressure is very low. Peripheral eosinophilia was dependent of the infection level. The immune response was similar in sheep infected with various numbers of flukes.     

中药复方制剂对球虫感染鸡血液免疫指标和酶活性影响

为了研究中草药复方制剂对人工感染柔嫩艾美耳球虫的鸡血液免疫指标和酶活性影响,选取80只罗曼蛋公雏饲喂至24日龄,随机分为4组,分别为非感染给药组、非感染非给药组、感染非给药组和感染给药组。27日龄时,感染组每只鸡接种1×105个孢子化球虫卵囊。感染球虫8d后,心脏采血,收集血清,采用半自动生化分析仪测定血清免疫指标:总蛋白(TP),白蛋白(ALB),球蛋白,免疫球蛋白IgA、IgG、IgM,血清酶指标:谷丙转氨酶(GPT)、谷草转氨酶(GOT)、碱性磷酸酶(ALP)。结果表明非感染非给药组的总蛋白、白蛋白、球蛋白血清浓度明显高于感染组,而感染给药组与非感染非给药组之间差异不显著(P0.05);感染组IgA、IgM含量显著高于非感染非给药组(P0.01),而IgG含量则显著低于非感染非给药组(P0.01),IgA、IgM含量感染给药组显著低于感染非给药组(P0.01),IgG含量感染给药组显著高于感染非给药组(P0.01);与非感染非给药组相比,感染组3种血清酶的活性均明显下降,感染给药组各种酶的活性均显著高于感染非给药组(P0.01)。表明该中草药复方制剂可降低柔嫩艾美耳球虫对鸡血清蛋白浓度的影响,使血清酶活性升高。     

A、J亚群禽白血病病毒感染肉用种鸡的诊断

通过流行病学调查、剖检病变和组织病理学观察,结合PCR技术检测病原核酸,确诊肉用种鸡群发生了由ALV—A和ALV—J感染而导致的淋巴细胞性白血病和骨髓细胞瘤型白血病。在检测的6只病鸡中,6只病鸡均感染了ALV—J,2只病鸡感染了ALV-A.     

In utero transmission of bovine leukemia virus

In an initial study, 18 calves born to cows persistently infected with bovine leukemia virus (BLV) were tested for infective virus and antibodies at birth, and no infected or seropositive animals were found. Four of these calves were maintained in quarters where infected animals were housed, and 3 of the 4 subsequently became infected. These were probably contact infections acquired during, or at some time after, birth. The remaining 14 calves were kept in isolation pens in a building housing no infected cattle. None of this group was found to be BLV infected during 1 year of observation. In further studies, 15 pregnant cows inoculated with BLV became infected. One abortion, considered to be unrelated to the BLV inoculation, occurred 38 days later. The remaining 14 cows gave birth to 1 dead and 14 live calves. The dead calf and its live twin were seropositive for BLV at birth, indicating that they had been infected in utero. The remaining 13 calves were negative for BLV antibodies at birth and remained so during 1 year of observation.     

Interaction of acute feline herpesvirus-1 and chronic feline immunodeficiency virus infections in experimentally infected specific pathogen free cats.

Cats with or without chronic feline immunodeficiency virus (FIV) infection were exposed to feline herpesvirus, type 1 (FHV-1). FIV infected cats became sicker than non-FIV infected cats and required more supportive treatment. However, there were no differences in the length of their illness or in the levels and duration of FHV-1 shedding. FHV-1 infection caused a transient neutrophilia at Day 7 with a rapid return to preinfection levels. The neutrophilia coincided with a transient lymphopenia that was accompanied by a decline in both CD4+ and CD8+ T-lymphocytes. A brief decrease in the CD4+/CD8+ T-lymphocyte ratio occurred at Day 14 in both FIV infected and non-infected cats. This decrease was mainly the result of an absolute and transient increase in CD8+ T-lymphocytes. CD4+ and CD8+ T-lymphocyte numbers and CD4+/CD8+ T-lymphocyte ratios returned to baseline within 4-8 weeks in both FIV infected and non-infected cats. FIV infected cats produced less FHV-1 neutralizing antibodies during the first 3 weeks of infection than non-FIV infected animals. The IgM FHV-1 antibody response was depressed in FIV infected cats whereas the IgG antibody response was unaffected. FHV-1 infection evoked a comparable transient loss of lymphocyte blastogenic responses to concanavalin A and pokeweed mitogen in both FIV infected and non-infected cats. However, response to pokeweed mitogen took longer to return to normal in FIV infected animals. Lymphocytes from FIV infected cats had a greater and more sustained proliferative response to FHV-1 antigen than non-FIV infected cats. The ongoing IgG antibody response to FIV was not affected by FHV-1 infection.     

Phenotype of hepatic infiltrates and hepatic lymph nodes of lambs primarily and challenge infected with Fasciola hepatica, with and without triclabendazole treatment

The phenotype of the hepatic inflammatory infiltrate and hepatic lymph nodes (HLN) was analysed in lambs primarily and challenge infected with Fasciola hepatica. Group 1 was primarily and challenge infected with two doses of 200 metacercariae (mc) each and was non-treated. Trickle infection was administered to five groups: group 2 was challenge infected and non-treated; group 3 was primarily infected and non-treated; group 4 was primarily infected and treated with triclabendazole (TCBZ) at 12 weeks postinfection (wpi); group 5 was treated at 4 wpi and challenge infected and group 6 was treated at 12 wpi and challenge infected. An uninfected group was used as the control. The distribution of T cell subpopulations (CD3, CD4 and CD8), and B cells (CD79alpha, IgM, IgG) was analysed. The hepatic inflammatory infiltrate was represented mainly by CD3 and CD4 T cells, and B cells (CD79alpha, IgG). These infiltrates were more severe (P < 0.05) in primarily (group 3) or challenge (groups 2, 5 and 6) trickle infected lambs than in the group single challenge infected (group 1). Cellular changes in HLN consisted in an increase of CD4 over CD8 T cells and an increase of B cells and IgG+ plasma cells, and they were more severe in primarily and challenge trickle infected groups than in the group infected with two larger doses of mc, although significant differences were not found with respect to all challenge trickle infected groups. The strong local cellular and humoral immune responses did not protect against subsequent infections, neither in non-treated lambs (group 2) nor in lambs treated with TCBZ at 4 wpi (group 5) or 12 wpi (group 6).     

Bovine genital campylobacteriosis (vibriosis): vaccination of experimentally infected bulls

The therapeutic efficacy of a Campylobacter fetus subsp venerealis bacterin was determined in experimentally infected bulls. Ten of twelve 5-year-old Angus bulls became infected after being infused intrapreputially with C fetus subsp venerealis. Of the 10 bulls, 6 were vaccinated with 5 ml of C fetus subsp venerealis vaccine on 2 occasions 4 weeks apart. Preputial washings of the vaccinated bulls were culturally negative by the 8th week after primary vaccination. None of the 18 heifers exposed to the vaccinated bulls became infected. The 4 infected, nonvaccinated bulls remained culturally positive to C fetus (P less than 0.002), and each bull infected at least 1 heifer (P less than 0.001). Two noninfected, nonvaccinated bulls remained culturally negative and did not infect any heifer. The 4 infected, nonvaccinated bulls were then vaccinated. Two bulls remained infected 9 weeks after primary vaccination, as determined by the virgin heifer test and cultural examination of preputial washings. Serologic data from 7 sampling periods were different (P less than 0.001) for vaccinated vs nonvaccinated bulls at 4 (against K antigen) or 6 (against O antigen) weeks after primary vaccination. Vaccination was effective in eliminating the infection in most of the infected bulls, but cannot be recommended as the sole measure of control in infected herds.     

鸡线虫对雏鸡成活率及发育的影响

通过雏鸡人工感染鸡蛔虫和异刺线虫的试验证明，鸡蛔虫、异刺线虫单独或混合感染，对雏鸡的成活率及发育均有程度不同的影响。与不感染对照组相比，感染３００个／只蛔虫卵的雏鸡成活率低１９％（Ｐ＜０．０５），死亡峰期在感染后７～１４天，增重低３０．１％（Ｐ＜０．０１），影响增重峰期为感染后第１～１０和２１～４０天；感染同量异刺线虫卵雏鸡成活率低１０．３％（Ｐ＞０．０５），死亡主因是组织滴虫病，增重低１６．６％（Ｐ＜０．０５），影响增重峰期在感染后第１１～２０天，混合感染减半量的两种虫卵，成活率低１４％（Ｐ＜０．０５），增重低３２．９％（Ｐ＜０．０１），死亡及发育受阻期与单独感染蛔虫卵组相似，但部分鸡死于组织滴虫病；单独感染减半量蛔虫卵，成活率低１７．３％（Ｐ＜０．０５），增重低１０．１％（Ｐ＞０．０５），死亡及影响增重峰期基本在感染后第１～１０天。     

Cell mediated immunity and specific IgG1 and IgG2 antibody response in natural and experimental canine leishmaniosis

In the present study, we have followed up Leishmania infantum infection in dogs: (1) naturally infected; (2) experimentally infected with amastigotes; and (3) experimentally infected with culture promastigotes. The main objective was to evaluate the differences of the humoral and cellular immune responses of each group. Sera from 12 beagle dogs were analysed for total anti-leishmanial antibodies and IgG1 and IgG2 subclasses by enzyme-linked immunosorbent assay (ELISA). Lymphoproliferation to L. infantum antigen was also performed. All naturally infected animals were symptomatic with a marked humoral response. Dogs inoculated with amastigotes were asymptomotic and presented lower antibody titres than naturally infected. Dogs inoculated with culture promastigotes were asymptomotic with no significant humoral response. Strong proliferative responses to Leishmania antigen was observed in dogs inoculated with promastigotes. In our experimental model, IgG1 antibody levels presented a similar pattern in all infected animals, and IgG2 reactivity was high in naturally infected dogs.     

The experimental infection of ponies with contagious equine metritis

Four pony mares were readily infected with the organism of contagious equine metritis by intracervical inoculation and one by coitus with an infected stallion. Infected mares developed an acute endometritis with local destruction of the endometrial epithelium. In 2 experimentally infected mares, infection appeared to have been spontaneously eliminated from the genital tract within 3 to 4 weeks. A third mare however remained persistently infected in the clitoral fossa over a long period and was a symptomless carrier. Four pony stallions were readily infected in the urethral fossa and the organism survived for varying periods without giving rise to any signs of infection. From 2 of these animals it appeared eventually to have been eliminated spontaneously. An experimentally infected stallion transmitted infection to a healthy mare by coitus. Bacteriological examination of infected pony stallions may occassionally give false negative results and fail to reveal the organism in the external genitalia. Repeated bacteriological examinations need to be undertaken before it can be concluded that a stallion is free of infection.     

TRANSMISSION OF A MUCOSAL DISEASE VIRUS INFECTION BETWEEN SHEEP

The transmission of mucosal disease virus (MDV) from infected ewes and their lambs to susceptible sheep was investigated. MDV was recovered from the amniotic fluid of an infected pregnant ewe and from the blood, nasal swabs and urine of hairy lambs. MDV infection was transmitted either at lambing, from infective foetal fluids or lambs, or later as a result of contact with a surviving with a hairy lamb and either aborted or gave birth to an infected hairy lamb. Adult sheep and 12-months-old sheep were less readily infected than were newborn lambs. Pregnant ewes were infected by contact with a hairy lamb and either aborted or gave birth to an infected hairy lamb. A method to minimise spread of the infection in the field is suggested.     

Experimental induction of the cutaneous form of Marek's disease in broilers

Straight-run chickens of the Ross broiler hybrid were experimentally infected with the skin homogenates of sound broilers, broilers conditionally edible, and broilers confiscated for alternations in skin. The chickens infected with the homogenates of healthy skin were negative in the Marek's disease test. In 17% of the chickens infected with the skin from the conditionally edible broilers, macroscopically observable cutaneous lesions were induced and 60% of the infected chickens had microscopic changes in the skin; visceral organs were always affected by the infection. In the chickens infected with the skin of a confiscated bird, the long storage exerted its unfavourable effect and the infected birds were negative in the Marek's disease test. Our results indicate that the active form of Marek's disease was induced.     

Preparation of monoclonal antibodies to Theileria sergenti and their reactivity to antigens in experimentally infected cattle

Two distinct monoclonal antibodies (3-H and 11-D) were produced against Theileria sergenti. These two new products, together with monoclonal antibody 1-G obtained in a previous study, were used to detect the parasites in experimentally infected cattle. During the first period of dexamethasone treatment, which was carried out to increase parasitemia in the infected cattle, the number of erythrocytes detected by 3-H, 11-D and 1-D increased in two experimentally infected calves. During the second period of dexamethasone treatment, the number of infected erythrocytes detected by 3-H and 11-D were similarly increased, but the number of infected erythrocytes detected by 1-G did not increase and infected erythrocytes in one calf were not detected by 1-G.     

Enzyme-linked immunosorbent assay for the detection of antibodies to Hypoderma bovis in cattle

An adaptation of the enzyme-linked immunosorbent assay has been shown to detect antibodies in the circulation of cattle infected with Hypoderma bovis. Strong positive reactions were obtained from all infected cattle, even those which harboured only one larva. A strong cross reaction was observed in sera taken from cattle infected with H lineatum, but not in cattle infected with Fasciola hepatica or Ostertagia ostertagi.