Sequence analysis and genetic variability of stearoyl CoA desaturase (SCD) gene in the Italian Mediterranean river buffalo

Stearoyl-CoA desaturase (SCD) plays a key metabolic role by changing the saturated FA content of ruminant milk and meat. In this study we characterized for the first time the stearoyl-CoA desaturase (SCD) gene in river buffalo (Bubalus bubalis) and investigated its genetic variability. On a total of 78 buffaloes, 15 SNPs were detected and 6 of them were preliminarily genotyped. In particular, the g.133A>C SNP was found to create a new consensus site for the SP1 binding site, thus generating a new tandem repeat in the promoter region. A preliminary association study with the milk fatty acid content showed that the C allele significantly affects the total desaturation index (P < 0.01). Linkage disequilibrium analysis allowed identification of 7 haplotypes and 4 tag SNPs. Such polymorphisms could represent useful genetic markers for association studies with fatty acid composition, but further studies are needed to evaluate their potential use to improve the nutritional quality of the dairy products.     

水牛化疗控制鄱阳湖地区血吸虫病传播的现场实验研究

目的探索水牛治疗是否在湖沼地区血吸虫病传播中的作用,为制定防治策略提供依据。方法将江西省鄱阳湖区2个血吸虫病重度流行村,分为实验(干预)组及对照组。实验组用吡喹酮治疗所有耕牛,以消灭可能血吸虫传染源;对照组,不治疗耕牛。两村居民按常规方法进行血吸虫病防治。结果连续5年观察结果表明,实验组居民感染率比对照组下降70%;3岁以下水牛感染率为2%~18%,3岁以上水牛感染率为0~2.9%。结论通过干预和对照组的研究表明,在血吸虫重度感染区,单纯对居民进行化疗是难以有效地控制血吸虫病的传播的,而通过化疗水牛在一定程度上能降低居民的再感染。本研究通过5年的观察,证实了对水牛进行治疗对控制血吸虫病的传播的效果可达70%,同时也证实了在感染的水牛中的大部分(89%)是小于3岁的水牛,这对我们今后制定有效的控制湖沼地区的血吸虫病对策提供了依据。     

Inter‐Epidemic and Between‐Season Persistence of Rift Valley Fever: Vertical Transmission or Cryptic Cycling?

Rift Valley fever (RVF) is an emerging zoonotic mosquito‐borne infectious disease that has been identified as a risk for spread to other continents and can cause mass livestock mortality. In equatorial Africa, outbreaks of RVF are associated with high rainfall, when vector populations are at their highest. It is, however, unclear how RVF virus persists during the inter‐epidemic periods and between seasons. Understanding inter‐epidemic persistence as well as the role of vectors and hosts is paramount to creating effective management programmes for RVF control. We created a mathematical model for the spread of RVF and used the model to explore different scenarios of persistence including vertical transmission and alternate wildlife hosts, with a case study on buffalo in Kruger National Park, South Africa. Our results suggest that RVF persistence is a delicate balance between numerous species of susceptible hosts, mosquito species, vertical transmission and environmental stochasticity. Further investigations should not focus on a single species, but should instead consider a myriad of susceptible host species when seeking to understand disease dynamics.     

免疫和非免疫耕牛感染日本血吸虫后虫卵肉芽肿大小的比较(英文)

本研究比较了免疫和非免疫耕牛，包括实验室或现场感染试验的黄牛（２３头）和水牛（２４头），肝脏日本血吸虫卵肉芽肿的体积大小。免疫耕牛系采用大剂量钴６０照射的日本血吸虫童虫为疫苗，经３次注射免疫后４ｗｋ，同时与非免疫耕牛一齐攻击感染正常的同种血吸虫尾蚴。结果表明，实验室感染的非免疫黄牛虫卵肉芽肿的平均体积为２４．２±１２．６ｍｍ３×１０－３，免疫黄牛的为２１．５±１４．９ｍｍ３×１０－３。现场感染的非免疫黄牛为２６．２±２２．０ｍｍ３×１０－３，免疫黄牛的为２０．９±１４．３ｍｍ３×１０－３。实验室感染非免疫水牛的为２６．８±１７．７ｍｍ３×１０－３，免疫水牛的为１６．７±１３．３ｍｍ３×１０－３。现场感染的非免疫水牛为２８．２±２１．０ｍｍ３×１０－３，免疫水牛的为１７．６±１５．３ｍｍ３×１０－３。表明免疫耕牛的虫卵肉芽肿平均体积均较非免疫耕牛的为小，除实验室感染的黄牛外，其它各组在统计学上均有显著性意义。因此，耕牛经注射钴６０照射童虫疫苗后的优点不仅能使攻击感染虫数明显减少，而且其肝脏中虫卵肉芽肿病变的体积也较小。显示了此种疫苗除有减虫作用外，同时还具有抗病损的保护作用。     

Immunohistochemical studies of the epididymal duct in Egyptian water buffalo (Bubalus bubalis)

Using immunohistochemistry (IHC), this study aimed to evaluate the regional distribution pattern of some biologically active proteins in the epididymis of Egyptian water buffalo and to determine the structural-functional relationships of the different epididymal structures. Wax-embedded sections from different regions of the epididymal duct from adult, clinically healthy, buffalo bulls were used. Primary antibodies against angiotensin converting enzyme (ACE), S-100, galactosyltransferase (GalTase), alpha smooth muscle actin (α-SMA), connexin 43 (Cx43) and vascular endothelial growth factor (VEGF) were used for immunohistochemical studies. The results showed that, in addition to the well-known principal and basal cells, the epididymal epithelium, similar to that of other species, possessed apical cells and intraepithelial leukocytes. IHC showed that, with the exception of VEGF which reacted negatively, all antibodies used displayed variable reactivity in the different epididymal structures. Apical cells expressed a strong reaction with ACE along the entire length of the duct. The principal cells in the caput epididymis exhibited a distinct reactivity with S-100 and GalTase. The peritubular muscular coat displayed a marked immunostaining for α-SMA and for Cx43. In conclusion these findings showed a regional-specific distribution pattern, distinct from that in bovine bulls. Some potential functional capacities, especially absorptive and secretory ones, are discussed in relation to the different epididymal regions.     

Rift Valley Fever in Kruger National Park: Do Buffalo Play a Role in the Inter‐Epidemic Circulation of Virus?

Rift Valley fever (RVF) is a zoonotic mosquito‐borne virus disease of livestock and wild ruminants that has been identified as a risk for international spread. Typically, the disease occurs in geographically limited outbreaks associated with high rainfall events and can cause massive losses of livestock. It is unclear how RVF virus persists during inter‐epidemic periods but cryptic cycling of the virus in wildlife populations may play a role. We investigated the role that free‐living African buffalo (Syncerus caffer caffer) might play in inter‐epidemic circulation of the virus and looked for geographic, age and sex patterns of Rift Valley fever virus (RVFV) infection in African buffalo. Buffalo serum samples were collected (n = 1615) in Kruger National Park (KNP), South Africa, during a period of 1996–2007 and tested for antibodies to RVF. We found that older animals were more likely to be seropositive for anti‐RVFV antibody than younger animals, but sex was not correlated with the likelihood of being anti‐RVFV antibody positive. We also found geographic variation within KNP; herds in the south were more likely to have acquired anti‐RVFV antibody than herds farther north – which could be driven by host or vector ecology. In all years of the study between 1996 and 2007, we found young buffalo (under 2 years of age) that were seropositive for anti‐RVFV antibody, with prevalence ranging between 0 and 27% each year, indicating probable circulation. In addition, we also conducted a 4‐year longitudinal study on 227 initially RVFV seronegative buffalo to look for evidence of seroconversion outside known RVF outbreaks within our study period (2008–2012). In the longitudinal study, we found five individuals that seroconverted from anti‐RVFV antibody negative to anti‐RVFV antibody positive, outside of any detected outbreak. Overall, our results provide evidence of long‐term undetected circulation of RVFV in the buffalo population.     

A review of recent research on Theileria parva: Implications for the infection and treatment vaccination method for control of East Coast fever

The infection and treatment (ITM) live vaccination method for control of Theileria parva infection in cattle is increasingly being adopted, particularly in Maasai pastoralist systems. Several studies indicate positive impacts on human livelihoods. Importantly, the first detailed protocol for live vaccine production at scale has recently been published. However, quality control and delivery issues constrain vaccination sustainability and deployment. There is evidence that the distribution of T. parva is spreading from endemic areas in East Africa, North into Southern Sudan and West into Cameroon, probably as a result of anthropogenic movement of cattle. It has also recently been demonstrated that in Kenya, T. parva derived from cape buffalo can ‘breakthrough’ the immunity induced by ITM. However, in Tanzania, breakthrough has not been reported in areas where cattle co‐graze with buffalo. It has been confirmed that buffalo in northern Uganda national parks are not infected with T. parva and R. appendiculatus appears to be absent, raising issues regarding vector distribution. Recently, there have been multiple field population genetic studies using variable number tandem repeat (VNTR) sequences and sequencing of antigen genes encoding targets of CD8+ T‐cell responses. The VNTR markers generally reveal high levels of diversity. The antigen gene sequences present within the trivalent Muguga cocktail are relatively conserved among cattle transmissible T. parva populations. By contrast, greater genetic diversity is present in antigen genes from T. parva of buffalo origin. There is also evidence from several studies for transmission of components of stocks present within the Muguga cocktail, into field ticks and cattle following induction of a carrier state by immunization. In the short term, this may increase live vaccine effectiveness, through a more homogeneous challenge, but the long‐term consequences are unknown.     

Host range and geographical distribution of Babesia sp. Mymensingh

Bovine babesiosis represents a serious threat to the cattle industry in the tropics and subtropics. Although several Babesia species infect cattle, only B. bovis, B. bigemina and B. divergens are known to cause clinical babesiosis. However, our recent study demonstrated that the newly discovered Babesia sp. Mymensingh might be a virulent species capable of causing clinical babesiosis in cattle. The objective of this study was to determine the host range and geographical distribution of Babesia sp. Mymensingh on a global scale. A total of 2,860 archived DNA samples from 2,263 cattle in Sri Lanka (n = 672), the Philippines (n = 408), Vietnam (n = 460), Uganda (n = 409), Brazil (n = 164) and Argentina (n = 150); 419 buffalo in Sri Lanka (n = 327) and Vietnam (n = 92); and 127 goats and 51 sheep in Vietnam were screened using a Babesia sp. Mymensingh‐specific PCR assay. Babesia sp. Mymensingh infection was detected in cattle, buffalo, sheep and goats. Cattle of all countries surveyed in this study except Brazil were found to be infected with Babesia sp. Mymensingh. The highest positive rates were recorded in cattle from the Philippines (11.3%) and Vietnam (9.6%), followed by Argentina (4.7%), Sri Lanka (1.5%) and Uganda (1.0%). Buffalo were found to be infected with this parasite in Sri Lanka (1.2%) and Vietnam (10.9%). Unexpectedly, Babesia sp. Mymensingh was also detected in sheep (2.0%) and goats (1.3%) from Vietnam. These findings were confirmed by PCR amplicon sequencing. In conclusion, our present findings indicate that Babesia sp. Mymensingh, which infects cattle, buffalo, sheep and goats, is endemic in Asia, Africa and South America.     

Determination of naturally occurring estrogenic hormones in cow’s and river buffalo’s meat by HPLC-FLD method

This study was performed to measure and compare the levels of steroid hormones [estrone (E₁), 17β-estradiol (E₂), and estriol (E₃)] and their conjugated metabolites in cow’s and river buffalo’s meat in two distinct follicular and luteal phases. Moreover, the possible effect of a heating process on steroid hormone concentration was also investigated. The collected meat (biceps femoris muscle) samples were subjected to liquid extraction, enzymatical deconjugation, and C18 solid-phase extraction. Estrogens were analyzed using high performance liquid chromatography equipped with a fluorescence detector. In the follicular phase the levels of steroid hormones (E₁ and E₂) in either tested species were higher than the luteal phase. Moreover, in the present study, E₁ concentration (free and deconjugated value, 16.2 ± 1.1 ng/L) was found to be the highest phenolic estrogen in beef, while the dominant estrogen in muscle of river buffalo was E₂ (free and deconjucated value, 23.3 ± 1.3 ng/L). The study revealed that animal species influenced the concentration of hormones (E₁ and E₂) in the samples. The heating process did not significantly change (p > 0.05) the levels of estrogens. The further findings of the present study showed that E₃ (deconjugated form) was only detected in the buffalo’s meat (15.8 ± 1.9 ng/L). These data suggest that although meat is one of the valuable nutrient sources for humans, there are, however, increasing concerns about the safety of meat due to the excessive presence of steroid hormones.     

Development of an Indirect ELISA Using Different Fragments of Recombinant Ncgra7 for Detection of Neospora caninum Infection in Cattle and Water Buffalo

Background:

Dense granules are immunodominant proteins for the standardization of immunodiagnostic procedures to detect neosporosis. In the presented study different fragment of a dense-granule protein was evaluated for serodiagnosis of Neospora caninum in cattle and water buffalo.

Methods:

NcGRA7, from N. caninum tachyzoites was amplified. PCR product and pMAL-c2X plasmid were digested with EcoR1 restriction enzyme and expressed in Escherichia coli to evaluate its competence for detection of anti- N. caninum antibodies with ELISA in comparison with commercial IDEXX ELISA. Furthermore, 230 sera of presumably healthy cattle and water buffaloes (108 cattle and 122 water buffaloes) were analyzed by both tests to determine the agreement of these two procedures.

Results:

Sensitivities and specificities of NcGRA7-based ELISA were 94.64% and 90.38% respectively using sera of cattle, but were 98.57% and 86.54% in the case of buffaloes respectively. A good correlation between the results of IDEXX ELISA and ELISA based on recombinant NcGRA7 for detecting N. caninum antibodies was appeared. Analyzing by Mc Nemar′s showed that NcGRA7-based ELISA has acceptable capability to differentiate the positive results in comparison with IDEXX ELISA.

Conclusion:

NcGRA7-based ELISA considering utilized new fragment of genomic DNA is a good tool for serodiagnosis of anti- N. caninum antibodies for screening and epidemiological purposes on cattle herd and water buffaloes as well.