Trichophyton verrucosum infection in cattle farms of Umbria (Central Italy) and transmission to humans

Trichophyton verrucosum is the most common ringworm agent in cattle. Epidemiology of cattle dermatophytoses in Central Italy is not clear. Its diffusion among cattle and herdsmen was investigated in 20 Umbrian farms, Central Italy. Hairs and scales were taken from 395 animals and 31 workers. Typical ringworm was present in 71.7% of cattle under 6 months and in 11% of animals over 6 months. T. verrucosum was isolated from 98.9% of symptomatic heads and was the most prevalent dermatophyte in all herds investigated (isolated in 18 of the 20 farms). T. mentagrophytes var. mentagrophytes was found in 16 symptomatic and in eight asymptomatic young animals. Prevalence of asymptomatic carriers of both species was significantly higher in young heads (21.1% vs. 8.1%) and the age below 6 months was the only statistically significant risk factor associated with dermatophytosis. About the workers, all the 14 men with lesions were positive for T. verrucosum; copresence of T. verrucosum and Microsporum gypseum was noticed in one case. Results indicate a high diffusion of T. verrucosum among both animals and humans in Umbrian farms and confirm the dermatophyte infection as a public health problem. Periodic epidemiological surveys, treatment of sick livestock and workers, cleaning/sanitisation of herds and vaccination programmes may be useful in controlling the infection.     

Aflatoxin B1 and fumonisin B1 affect the oxidative status of bovine peripheral blood mononuclear cells

Mycotoxins are secondary metabolites having a high cytotoxic potential. They are produced by molds and released in food and feed. To date, the mechanisms underlying the mycotoxin-induced cytotoxicity have not been fully clarified. The induction of oxidative stress, as a possible mechanism, has been postulated. This in vitro study was focused on the effect of two widely occurring mycotoxins, aflatoxin B₁ (AFB₁) and fumonisin B₁ (FB₁), on the oxidative status of bovine peripheral blood mononuclear cells (PBMC) incubated for 2 and 7 days at different levels of AFB₁ (0, 5 and 20 μg/ml) and FB₁ (0, 35 and 70 μg/ml). Reactive oxygen metabolites (ROM), intracellular thiols (SH), malondialdehyde (MDA) and gene expression of cytoplasmic superoxide dismutase (SOD) and glutathione peroxidase (GSHPX-1) were measured on PBMC after incubation. The highest concentration of AFB₁ and all concentrations of FB₁ caused an increase (p < 0.05) of intracellular ROM without any time dependent effect. Intracellular SH decreased with 20 μgAFB₁/ml (p < 0.05) and the effect was particularly marked after 7 days of exposure. Intracellular SH were not affected by FB₁ even though a lower (p < 0.05) SH level after 2 days exposure than after 7 days was observed. MDA increased (p < 0.05) in AFB₁ or FB₁ treated PBMC. The exposure to FB₁ for 7 days increased MDA (p < 0.05) only in cells treated with 70 μg/ml. Exposure of PBMC to AFB₁ reduced SOD mRNA while FB₁ decreased both SOD and GSHPX-1 mRNA abundance. These results demonstrate that, even though by different mechanisms, AFB₁ and FB₁ may induce cytotoxicity through an impairment of the oxidative status of PBMC.     

饲喂不同水平热处理大豆对肉牛体组织和血清中类胰岛素生长因子-Ⅰ、生长激素、胰岛素和瘦素水平的影响

本试验选用12头24月龄杂交肉牛(利木赞×鲁西黄牛,平均体重为532.6±20.9kg)作为试验牛,研究了不同水平的热处理大豆对肉牛背最长肌、背部脂肪、肝脏和血液中类胰岛素生长因子-Ⅰ和生长激素的影响。试验牛被随机分为三组,每组包括4头动物,试验日粮分别含有3.60%、10.06%和15.72%的粗粉碎热处理大豆,记为处理1、处理2和处理3。试验期为28d,试验结束后采集背最长肌、背部脂肪、肝脏和血液样品,测定类胰岛素生长因子-Ⅰ、瘦素、生长激素和胰岛素水平。试验结果表明,三个处理组肝脏和背部脂肪中的类胰岛素生长因子-Ⅰ水平之间没有显著差异(P>0.05);添加10.06%大豆组的背最长肌的胰岛素样生长因子-Ⅰ水平显著高于其他两个处理组(P<0.05);三个处理组的肝脏和背部脂肪中的瘦素含量没有显著差异(P>0.05)。处理1和处理2背最长肌中的瘦素水平显著高于处理3(P<0.05)。粗脂肪的采食量与肝脏中IGF-I的水平之间存在显著的二次曲线关系。试验结果说明,如果热处理大豆的添加量恰当(在本试验中为10.06%),可以提高背最长肌中的IGF-Ⅰ水平,进而提高肉牛生产性能。试验还发现,粗脂肪采食量是影响肉牛...     

Pathogenesis of bovine neosporosis

The protozoan parasite Neospora caninum is a major pathogen of cattle and dogs, being a significant cause of abortion in cattle in many countries. It is one of the most efficiently transmitted parasites, with up to 90% of cattle infected in some herds. The pathogenesis of abortion due to Neospora is complex and only partially understood. Losses occur after a primary infection during pregnancy but more commonly as the result of recrudescence of a persistent infection during pregnancy. Parasitaemia is followed by invasion of the placenta and fetus. It is suggested that abortion occurs when primary parasite-induced placental damage jeopardises fetal survival directly or causes release of maternal prostaglandins that in turn cause luteolysis and abortion. Fetal damage may also occur due to primary tissue damage caused by the multiplication of N. caninum in the fetus or due to insufficient oxygen/nutrition, secondary to placental damage. In addition, maternal immune expulsion of the fetus may occur associated with maternal placental inflammation and the release of maternal pro-inflammatory cytokines in the placenta. Thus N. caninum is a primary pathogen capable of causing abortion either through maternal placental inflammation, maternal and fetal placental necrosis, fetal damage, or a combination of all three. The question of how N. caninum kills the fetus exposes the complex and finely balanced biological processes that have evolved to permit bovine and other mammalian pregnancies to occur. Defining these immunological mechanisms will shed light on potential methods of control of bovine neosporosis and enrich our understanding of the continuity of mammalian and protozoal survival.     

Endotoxin and mammalian host responses during experimental disease

Endotoxin is an integral component of the outer membrane of Gram-negative bacteria and a prime example of unique and highly conserved bacterial surface molecules that engage with the innate immune system of the mammalian host via pattern recognition receptors on a range of host cells. The results of this interaction, which may be beneficial or detrimental to the development and welfare of the host, are reviewed, focusing on the different sensitivities and consequences in a range of hosts of experimental exposure to endotoxin, the disease outcomes and recent developments in our understanding of the mechanisms involved.     

Prospects for recombinant vaccines against Babesia bovis and related parasites

Babesial parasites infect cattle in tropical and temperate regions of the world and cause significant morbidity and mortality. Discovery of protective antigens that could be used in a killed vaccine has been slow and to date there are few promising vaccine candidates for cattle Babesia. This review describes mechanisms of protective innate and adaptive immune responses to babesial parasites and different strategies to identify potentially protective protein antigens of B. bovis, B. bigemina, and B. divergens. Successful parasites often cause persistent infection, and this paper also discusses how B. bovis evades and regulates the immune response to promote survival of parasite and host. Development of successful non-living recombinant vaccines will depend on increased understanding of protective immune mechanisms and availability of parasite genomes.     

Theileria parva and the bovine CTL response: down but not out?

Theileria parva is a tick-borne intracellular protozoan of cattle, with obligate sequential differentiation stages in lymphocytes and erythrocytes. Immunity is mediated by cytotoxic T lymphocytes (CTL) that target and clear parasitized lymphocytes but allow persistence of infected erythrocytes, which are required for transmission to the tick. The life cycle of T. parva is haploid with the exception of a brief diploid stage in the tick vector during which sexual recombination occurs. There is evidence for antigenic diversity in field parasite populations, although broad immunity can be acquired following exposure to a limited number of strains. The CTL response in individual animals is tightly focused and its specificity is strongly influenced by major histocompatibility complex (MHC) phenotype. This review discusses the issue of how CTL immunity is likely to impact on parasite population structure in the light of available information on diversity of the parasite and its ability to recombine.     

牛带绦虫实验感染乳牛的病理学观察

目的观察牛带绦虫感染乳牛的病理学改变。方法采用贵州从江县的牛带绦虫孕节灌喂荷兰霍尔斯坦种乳牛1头,隔离饲养。于感染后35d剖检,切取病变组织制片、HE染色,作病理组织学检查。结果乳牛的肝脏、心肌、肩胛肌、肾脏等均有囊尾蚴寄生,致相应组织器官出现不同程度的变性、坏死,炎细胞浸润等病理损害。其中以肝脏病变最为突出,多处肝细胞小灶性坏死及片状坏死,大量中性粒细胞浸润。结论牛带绦虫感染霍尔斯坦乳牛35d即可致多组织多器官囊尾蚴寄生,并出现不同程度的病理改变,特别是肝脏,囊尾蚴寄生最多,病理损害较重。     

Cytogenetic comparison between Vietnamese sika deer and cattle: R-banded karyotypes and FISH mapping

R-banded chromosomes of Vietnamese sika (VS) deer (Cervus nippon pseudaxis, 2N = 66), a threatened subspecies of sika deer endemic to Vietnam, are presented for the first time and were compared with bovine R-banded chromosomes to define a standard karyotype. Nineteen VS deer autosomes (CNP) were identified on the basis of the banding pattern relative to bovine chromosomes (BTA), while hypotheses for the remaining thirteen were proposed from comparisons with the published deer genetic map, BTA 1, 2, 5, 6, 8 and 9 each equivalent to two separate acrocentric CNP chromosomes and BTA 26 and 28 associated in a tandem fusion. To confirm these hypotheses, probes for the twenty-nine Texas nomenclature type I markers specific for each cattle autosome, sixteen other type I and fourteen microsatellite markers were used in FISH experiments on VS deer chromosomes. CNP7 presented the most complex rearrangement as compared with cattle chromosomes. A complete correspondence between VS deer and cattle chromosomes was established and it was extended with a comparison with the human karyotype to transfer human map information to this species of scientific and economic interest. Moreover, this work anchors the deer genetic linkage map to chromosome-specific markers. This revised version was published online in July 2006 with corrections to the Cover Date.