Prevalence of antibodies to Theileria equi and Babesia caballi in horses from northeastern Mexico.

The objective of this study was to obtain an estimate for seroprevalences of Theileria equi (Babesia equi) and Babesia caballi in horses from northeastern Mexico. Sera were collected in spring of 2007 in 248 clinically healthy horses used for different purposes. Antibodies were detected by the indirect immunofluorecent technique. The overall seroprevalence was 61.7% and those for T. equi and B. caballi were 45.2% and 27.4%, respectively. Horse purpose, sex, and age group were not associated with infection with Theileria equi or Babesia caballi.

The impact of potential mitigation strategies on the predicted spread of foot and mouth disease in white-tailed deer in south Texas.

The United States has been free of FMD since the 1920s. Faced with an incursion of FMD virus that might involve wildlife species, it is crucial that appropriate mitigation strategies be applied rapidly to control the disease. Disease spread models can be used to evaluate the design of optimal strategies. Using a previously developed susceptible-infected-recovered geographic automata model (Sirca) to simulate the spread of FMD through white-tailed deer populations in south Texas, we conducted a series of experiments to determine how pre-emptive mitigation strategies applied to white-tailed deer populations might impact the predicted magnitude and distribution of outbreaks following FMD virus incursion. Based on previously derived deer distributions in the two ecoregions found within the study area, simulated outbreaks were evaluated by comparing the median number of deer predicted to be infected and the median area predicted affected for a baseline scenario and 3 mitigation strategies: targeted cull, random cull and targeted depopulation buffer. Substantial differences were observed in the predicted magnitude of outbreaks both by mitigation strategy and by ecoregion: depending on the ecoregion, the creation of a targeted depopulation buffer could reduce the number of deer predicted infected by up to 52%, and the area affected by up to 31%. Results suggest that the outcome of an FMD incursion that involves wildlife species, such as white-tailed deer in south Texas, might depend on both where the incursion occurs and the type of pre-emptive mitigation strategy applied.

Characterization of recombinant antibodies developed for capturing enterohemorrhagic Escherichia coli O157:H7.

Escherichia coli O157:H7, an emerging cause of food-borne disease with the occurrence of an estimated 20,000 illnesses and 250 deaths each year in the United States, has now been reported from several countries worldwide. Infections with this bacteria, which follows the ingestion of contaminated food by humans, causes bloody diarrhea, hemolytic uremic syndrome (HUS), and renal disease, that can have serious health implications. The source of food contamination is usually associated with animals, mainly cattle. Many cattle become infected early in life when they are exposed to an environment that is contaminated by other animals shedding the organisms in their feces. Detection of E. coli O157:H7 in feces or contaminated food samples requires tests with high sensitivity, which is increased by the use of monoclonal antibodies. However, the production of concentrated monoclonal antibodies in ascites raises animal welfare concerns, and can be expensive. In this study, single chain of variable fragment (scFv) molecules were developed from hybridoma clones that produce immunoglobulins specific for the LPS and flagella antigen of E. coli O157:H7 using phage display technology. The reactivity of the soluble scFv for their respective antigens was preserved in ELISA and by partial inhibition of bacterial agglutination with polyclonal antiserum. Furthermore, the scFv were able to capture E. coli O157:H7 bacteria demonstrating their potential use in diagnostic assays.

Educational preparedness of veterinarians for foreign animal diseases.

Veterinary medical education in FADs has been and will continue to be critically important if veterinarians are expected to fulfill the profession's primary obligations to society--those of protecting our animals' health, conserving our animal resources, and promoting public health. It is imperative that curricula and instruction in veterinary schools and colleges provide the depth and breadth of knowledge and understanding necessary to prepare all veterinarians, including those in private practice, for their key role in defending against FADs. Development and implementation of governmental and military programs to diagnose, prevent, control, and eradicate FADs will require a dedicated cadre of public sector veterinarians who have a solid educational foundation in FADs and understand the contemporary issues and global challenges we face. Animal-related industries, associations, and organizations will increasingly rely on well-educated veterinarians to help guide them in ways that will protect animals, clientele, consumers, and trading partners from effects of FADs. Agencies and organizations concerned with conservation of animal resources will require veterinary expertise necessary to prevent FADs in a multitude of animal species, including marine animals, wildlife, endangered species, zoologic specimens, and important genetic lines as well as our domestic companion and livestock species. Species affected by FADs also include human beings for those disease agents with zoonotic potential; thus, veterinary education also plays a key role in public health.

Biochemical detection of esterases in the adult female integument of organophosphate-resistant Boophilus microplus (Acari: Ixodidae).

Esterase activity was present in the integument of adult female Boophilus microplus (Canestrini) ticks that are resistant to organophosphates (OP). Three esterases were purified from adult integument, which hydrolyze the substrates p-nitrophenylacetate and beta-naphthyl acetate after comparison of OP-resistant strain and an OP-susceptible strains. The esterases purified by ion-exchange chromatography were characterized using different esterase inhibitors; eserine sulfate, diethyl p-nitrophenyl phosphate (paraoxon), para-hydroxyl-mercuribenzoate (pHMB), and diisopropylphosphofluoridate (DFP). All of the esterases had a molecular mass of 64 Kd (PAGE), but were characterized based on the esterase inhibitor effects as a B-esterase with beta-naphthyl acetate affinity, a carboxylesterase with beta-naphthyl acetate and p-nitrophenyl acetate affinity, and one A-Esterase (nonspecific esterase) with p-nitrophenyl acetate affinity. The described esterases are an important detoxification mechanism in B. microplus ticks at the integument. We describe also a microplate biochemical assay for the detection of esterase activity in the tick integument, potentially a useful tool to detect esterase-mediated OP resistance in B. microplus ticks.

Global veterinary leadership.

The public needs no reminder that deadly infectious diseases such as FMD could emerge in any country at any moment, or that national food security could be compromised by Salmonella or Listeria infections. Protections against these risks include the knowledge that appropriate and equivalent veterinary education will enable detection and characterization of emerging disease agents, as well as an appropriate response, wherever they occur. Global veterinary leadership is needed to reduce the global threat of infectious diseases of major food animal and public health importance. We believe that the co-curriculum is an excellent way to prepare and train veterinarians and future leaders who understand and can deal with global issues. The key to the success of the program is the veterinarian's understanding that there is a cultural basis to the practice of veterinary medicine in any country. The result will be a cadre of veterinarians, faculty, and other professionals who are better able (language and culture) to understand the effects of change brought about by free trade and the importance of interdisciplinary and institutional relationships to deal effectively with national and regional issues of food safety and security. New global veterinary leadership programs will build on interests, experience, ideas, and ambitions. A college that wishes to take advantage of this diversity must offer opportunities that interest veterinarians throughout their careers and that preferably connect academic study with intensive experiential training in another country. At its best, the global veterinary leadership program would include a partnership between veterinarians and several international learning centers, a responsiveness to the identified international outreach needs of the profession, and attention to critical thinking and reflection. The global veterinary leadership program we have described is intended to be a set of ideas meant to promote collaboration, coalitions, and discussion among veterinarians and veterinary educators who may be intrigued by the concept. The impact of the program can be summarized as follows: Outreach Programs: The global veterinary leadership program will establish new partnerships between veterinarians and veterinary college faculty as they supervise the international internships and see a relationship between their goals and the value of food safety to this country. Strategic Opportunity: The program will build on the critical role that US veterinarians and veterinary colleges already play in strengthening the safety of free trade in this hemisphere. Diversity in an Age of Specialization: The program will combine a global orientation, language ability, and access to comprehensive, research- and economic-related work/study opportunities to expose veterinarians to the expanding world market for veterinary expertise. New Linkages Through Corporate Partners: Through the success and high visibility of current research and education programs, most veterinary colleges are well positioned to engage industry, government, and university leaders in ways to use the proposed program to increase the flow of new ideas and talent into the world food enterprise. International Funding: A new partnership among veterinarians, industry, government, and university leaders can coordinate strong multilateral requests for funding from national and international sources. An Interdisciplinary Strategy that Benefits Veterinary Medicine: The program will combine the diverse veterinary research and education system with our strong national and international network of collaborators to provide globally competent veterinarians who will be needed for the corporate and public opportunities of the future.

Babesiosis and heartwater: threats without boundaries.

Suppose one of your clients from southern Florida starts talking about cattle egrets while you are vaccinating her cat. It seems she found a nearly dead egret near the cattle pen a few days ago, picked it up, and noticed a number of what looked like small ticks on the legs. Or, suppose you are called out to a small dairy in central Texas to look at some cows that are feverish and anemic. The first animal you examine has a few brown ticks attached just under the tail. Finally, perhaps you are looking at a lame tortoise for a reptile fancier, a new client, and find a large, colorful tick on a hind leg, well up under the shell. Ring any bells? Egrets are great hosts for the immature stages of Amblyomma ticks and have been captured and marked in the eastern Caribbean, then recaptured in the Florida Keys. Those cattle ticks in Texas might be acaricide-resistant Boophilus ticks that originated in Mexico. The Amblyomma tick on the tortoise could well have "hitch-hiked" all the way from South Africa. By now you remember that both Amblyomma and Boophilus ticks are efficient vectors of two tickborne diseases in this hemisphere, heartwater (in the case of Amblyomma) and babesiosis (transmitted by Boophilus ticks). Both of these diseases are exotic to the United States, and because our livestock are considered to be totally susceptible, an introduced infection could result in high initial death losses (approximately 70%); thus, both the ticks and the diseases pose immediate threats to the health and economic security of United States animal industries. Most importantly, you, whether as a small animal or large animal practitioner, are the first line of defense against such exotic diseases and their vectors.

In vitro generation of organophosphate resistant boophilus microplus (Acari: Ixodidae) cell lines.

Three organophosphate resistant Boophilus microplus Canestrini cell lines were generated by exposing B. microplus VIII-SCC cell line to incrementally increased toxic concentrations of the acaricide coumaphos. The development of resistance was evidenced by LC50 values elevated over those of control cells. The resistant cell lines selected in higher concentrations of organophosphate, designated C44 and C54, also had significantly slower duplication rates than a resistant cell line selected in lower concentrations of coumaphos (C34) and the nonresistant control cells. Resistant cell lines C44 and C54 also had significantly higher levels of esterase after exposure to coumaphos than resistant cell line C34 and the nonresistant controls. These in vitro results agree with reports of increased esterase activity associated with organophosphate resistance in B. microplus ticks in vivo.

In vitro detection of acaricide resistance in Boophilus microplus (Acari: Ixodidae).

The cattle tick Boophilus microplus causes significant economic losses in cattle in the tropical areas of Central and South America. Acaricides are widely used to control tick infestations, with the consequent selection of tolerant and resistant subpopulations. Detoxifying enzymes, and esterases in particular, have been associated with organophosphate resistance in Mexican isolates of B. microplus ticks. Here, we present results of the biochemical detection of esterases and oxidases in 20 isolates of larvae and adult ticks and the effect of esterase and oxidase inhibitors on larvae and adult stages of the tick. Our results indicate the presence of significant differences both in vivo and in vitro between esterase and oxidase activities of OP-susceptible and OP-resistant isolates, even when samples were collected in the same area. The importance of such differences in regionalized integrated pest management and in the US Tick Eradication Program is discussed.

Detección de las enzimas detoxificantes B esterasas en Culex quinquefasciatus (Say), Boophilus microplus (Canestrini), Amblyomma cajennense (Fabricius) y Blatella germanica (L) por medio de zimogramas / Detection of the detoxifying enzymes B esterases in Culex quinquefasciatus (say), Boophilus microplus (canestrini), Amblyomma cajennense (Fabricius) and Blatella germanica (L) with the use of zymograms

Extractos crudos de especímenes de Culex quinquefasciatus (Say), Boophilus microplus (Canestrini), Amblyomma cajennense (Fabricius) y Blatella germanica (L) fueron analizados por medio de electroforesis en gel de poliacrilamida, para detectar actividad de B esterasas. Los extractos crudos de una cepa resistente a organofosforados de B. microplus presentaron diferencias en el patrón electroforético cuando fue comparado con una cepa susceptible a organofosforados de larvas de B. microplus. El extracto crudo de Cx. quinquefasciatus cepa florida presentó una banda de marcada actividad. En la muestra de A. cajennense se encontró una banda de diferente pero molecular; y en el extracto crudo de Blatella germanica se localizaron dos bandas de diferente peso molecular. Se utilizaron suero y eritrocitos de origen bovino como testigos.