Rabies Still a Menace

COLLEGE STATION, (TAMU) – World Rabies Day is September 28, 2012.It is a day to raise awareness about the impact of human and animal rabies. More than 55,000 people die from rabies worldwide every year, a rate of one person every 10 minutes. This is an astonishing number, especially because rabies in humans in 100 per cent preventable. Most of these cases are transmitted to humans by dogs.

World Rabies Day events have been held in 150 countries, and have vaccinated 7.7 million dogs to date. World Rabies Day was created in 2006 by the Global Alliance for Rabies Control. The Alliance consisted of researchers and professionals involved with human and animal healthcare, including Dr. Leon Russell, professor in the Texas A&M College of Veterinary Medicine & Biomedical Sciences (CVM).

Russell explained that the goal of World Rabies Day is to reduce the amount of rabies cases throughout the world by ensuring adequate animal vaccination and control, educating people who may be at risk, and increasing access to appropriate medical care for those bitten by rabies infected animals.  For more information about getting animals vaccinated on World Rabies Day in your area, please contact your local veterinarian.

While there are various strains of rabies, dogs are the primary source for transmission to humans across the globe. However, canine rabies virus strain has been eradicated in the United States because of proper and complete vaccination procedures.

“Our hope is to eliminate canine rabies across the globe,” Russell said. “Rabies is completely preventable. We want people to understand the importance of vaccinating against the disease. But while canine rabies has been eliminated, there are still treats to humans and pets in the United States, so people, particularly pet owners need to take precautions.”

Dogs and cats contract rabies primarily from skunks, raccoons, and bats in the United States. These canine and feline pets serve as “bridge animals” or carriers of rabies between wildlife hosts and people. Russell explained that if you suspect your dog or cat has been exposed to a rabid animal, you should take your pet to a veterinarian immediately.

While Russell says that it is good to be aware of potentially rabid bats, skunks, and raccoons, nothing is as effective in preventing rabies as vaccination of your canine and feline pets.

“There are two types of vaccines. One protects pets for one year, the other for three years,” Russell said. “They are both great vaccines, and sometimes local ordinances or price dictates which one pet owners choose – but regardless, pets should always be routinely vaccinated against rabies.”

In addition to dogs and cats, Russell recommends vaccinating cattle and equines as well. While dogs and cats predominantly contract rabies from various wildlife species (skunks, raccoons, bats), horses and cattle most often contract rabies from skunks.

“Horses that are stalled, particularly at night, should be vaccinated,” Russell said. “We’ve seen cases of horses that contract rabies from a skunk that gets into the stall; it isn’t common, but it does happen. It’s better to be safe than sorry when it comes to rabies. Vaccinating your animals is the best prevention.”

Concurrent Ivermectin and Solanum spp. Toxicosis in a Herd of Horses.

J Vet Intern Med. 2012 Sep 4;

Authors: Norman TE, Chaffin MK, Norton PL, Coleman MC, Stoughton WB, Mays T


BACKGROUND: Representatives from a herd of horses with acute onset of neurologic signs after administration of ivermectin presented for evaluation and treatment. OBJECTIVES: Describe clinical signs of horses intoxicated by ingestion of Solanum sp. and administered ivermectin. ANIMALS: Six of 11 affected unrelated horses presented for evaluation and treatment. The remaining 5 affected horses were treated at the farm. Four additional horses, housed separately, were unaffected. METHODS: Case series is presented. Serum ivermectin concentrations were evaluated in the 6 hospitalized horses. The remnants of the tubes of ivermectin paste were analyzed for ivermectin concentration. The hay fed to the affected horses was analyzed for the presence of toxic plants. RESULTS: Serum ivermectin concentrations were higher than expected, given the dosage of ivermectin administered. The ivermectin concentration remaining in the administration tubes did not exceed specifications. The hay was heavily contaminated by 2 Solanum species. All horses returned to normal neurologic function with supportive care. CONCLUSIONS AND CLINICAL IMPORTANCE: Horses might exhibit signs of ivermectin toxicity after appropriate dosing of the drug if they concurrently consume toxic plants of the Solanum family.
PMID: 22947027 [PubMed – as supplied by publisher]

Comment by Rogue Equine Hospital:  Solanum, the nightshades, horsenettles and relatives, are a large and diverse genus of annual and perennial plants. They grow as forbs, vines, subshrubs, shrubs, and small trees, and often have attractive fruit and flowers.


Variation in fecal egg counts in horses managed for conservation purposes: individual egg shedding consistency, age effects and seasonal variation.

Parasitology. 2012 Aug 16;:1-14

Authors: Wood EL, Matthews JB, Stephenson S, Slote M, Nussey DH


SUMMARY Cyathostomins are the most prevalent equine intestinal parasites and resistance has been reported in these nematodes against all 3 licensed anthelmintic classes. Strategies need to be developed that are less dependent upon drugs and more reliant on management-based control. To develop these we need to understand natural transmission patterns better. Here, we analysed longitudinal fecal egg count (FEC) data from 5 pony populations used for conservation purposes. We tested how egg excretion varied amongst populations and individuals, and how this was affected by age and climate. There was evidence for consistency in FECs over time at the individual level; this was generally weak and accounted for <10% of the total variance. Animals <5 years old had higher FECs and there was profound seasonal variation in FECs, with highest levels recorded in spring/summer. Effects of monthly temperature and rainfall explained most, but not all, of the observed seasonal variation and associations between climate measures and FECs were stronger in younger versus adult animals. One population was occasionally treated with anthelmintics and analysi

Rogue Equine Comment:  This abstract underscores the importance of individually performed Fecal Egg Counts and the variations of age, climate and external factors.  Patterns of resistance to virtually all major anthelmentics by cyathostomes (small strongyles) continue to increase, highlighting the importance of management.

Hendra virus: an emerging paramyxovirus in Australia.

Lancet Infect Dis. 2012 Aug 23;

Authors: Mahalingam S, Herrero LJ, Playford EG, Spann K, Herring B, Rolph MS, Middleton D, McCall B, Field H, Wang LF


Hendra virus, first identified in 1994 in Queensland, is an emerging zoonotic pathogen gaining importance in Australia because a growing number of infections are reported in horses and people. The virus, a member of the family Paramyxoviridae (genus Henipavirus), is transmitted to horses by pteropid bats (fruit bats or flying foxes), with human infection a result of direct contact with infected horses. Case-fatality rate is high in both horses and people, and so far, more than 60 horses and four people have died from Hendra virus infection in Australia. Human infection is characterised by an acute encephalitic syndrome or relapsing encephalitis, for which no effective treatment is currently available. Recent identification1 of Hendra virus infection in a domestic animal outside the laboratory setting, and the large range of pteropid bats in Australia, underpins the potential of this virus to cause greater morbidity and mortality in both rural and urban populations and its importance to both veterinary and human health. Attempts at treatment with ribavirin and chloroquine have been unsuccessful. Education, hygiene, and infection control measures have hitherto been the mainstay of prevention, while access to monoclonal antibody treatment and development of an animal vaccine offer further opportunities for disease prevention and control.

PMID: 22921953 [PubMed – as supplied by publisher]

Rogue Equine Comment:  We are fortunate in the US that no known virus exists which is similar to Hendra.

Do horses expect humans to solve their problems?

Do horses expect humans to solve their problems?from pubmed: horse by Lesimple C, Sankey C, Richard MA, Hausberger M Related Articles

Do horses expect humans to solve their problems?

Front Psychol. 2012;3:306

Authors: Lesimple C, Sankey C, Richard MA, Hausberger M


Domestic animals are highly capable of detecting human cues, while wild relatives tend to perform less well (e.g., responding to pointing gestures). It is suggested that domestication may have led to the development of such cognitive skills. Here, we hypothesized that because domestic animals are so attentive and dependant to humans’ actions for resources, the counter effect may be a decline of self sufficiency, such as individual task solving. Here we show a negative correlation between the performance in a learning task (opening a chest) and the interest shown by horses toward humans, despite high motivation expressed by investigative behaviors directed at the chest. If human-directed attention reflects the development of particular skills in domestic animals, this is to our knowledge the first study highlighting a link between human-directed behaviors and impaired individual solving task skills (ability to solve a task by themselves) in horses.

PMID: 22936923 [PubMed – in process]

Early exercise in the horse

Abstract: Across all equestrian disciplines, the single largest reason for wastage is musculoskeletal injury. It is, therefore, of importance that management and competition structures are in place to optimize the development of the equine musculoskeletal system to minimize wastage.Data from other species and, in particular, humans have demonstrated the benefit of early exercise and the dire consequences of inactivity. The horse has evolved as a cursorial animal capable of covering up to 10 km/d within 9 days of birth. Yet, modern equine management systems restrict, rather than promote, early exercise. Foals were shown to have a positive response to early preweaning paddock exercise (greater cartilage health), and more recent work has demonstrated that exercise over and above that normally occurring with pasture-reared foals, introduced as early as 3 weeks old, had positive effects on the equine musculoskeletal system. The response of juvenile horses to additional exercise is because of the tissue being responsive to priming. Epidemiological data indicate that the window for tissue modification may still be open when the horse is a yearling and even as a 2 year old.However, the method in which the exercise is applied may be of as much importance as the timing of the stimuli. A recent prospective study of both Thoroughbred and Standardbred horses demonstrated that the horses that entered training as 2 year olds had longer and more successful racing careers than those that entered training later in life. It would appear that even the initial stages of training are enough to provide a positive stimulus, as horses first registered with a trainer at 2 years old had the same advantages as those that raced as 2 year olds.The physiological, clinical, and epidemiological data indicate that, rather than restrict exercise and the use of horses at a young age, we should realign expectations with the capability of the horses’ musculoskeletal system and evolutionary template to maximize orthopedic health.

Equine insect bite hypersensitivity: What do we know?

from pubmed: horse by Schaffartzik A, Hamza E, Janda J, Crameri R, Marti E, Rhyner C

Equine insect bite hypersensitivity: What do we know?

Vet Immunol Immunopathol. 2012 Apr 3;

Authors: Schaffartzik A, Hamza E, Janda J, Crameri R, Marti E, Rhyner C

Insect bite hypersensitivity (IBH) is an allergic dermatitis of the horse caused by bites of insects of the genus Culicoides and is currently the best characterized allergic disease of horses. This article reviews knowledge of the immunopathogenesis of IBH, with a particular focus on the causative allergens. Whereas so far hardly any research has been done on the role of antigen presenting cells in the pathogenesis of IBH, recent studies suggest that IBH is characterized by an imbalance between a T helper 2 (Th2) and regulatory T cell (T(reg)) immune response, as shown both locally in the skin and with stimulated peripheral blood mononuclear cells. Various studies have shown IBH to be associated with IgE-mediated reactions against salivary antigens from Culicoides spp. However, until recently, the causative allergens had not been characterized at the molecular level. A major advance has now been made, as 11 Culicoides salivary gland proteins have been identified as relevant allergens for IBH. Currently, there is no satisfactory treatment of IBH. Characterization of the main allergens for IBH and understanding what mechanisms induce a healthy or allergic immune response towards these allergens may help to develop new treatment strategies, such as immunotherapy.

PMID: 22575371 [PubMed – as supplied by publisher]


Comment:  Progress on an old age problem.  Always known by deduction,  Culicoides spp. cause dramatic skin reactions in the horse.  The feeding process of Culicoides leaves some horses with profound swelling and intense itching.  To date, teh most effective tool has been exogenous steroid therapy.  As with many mysteries, the first step in the unlocking process is more understanding.  Perhaps hyposensitization therapy is in the future.

Effect of livestock manures on the fitness of house fly, Musca domestica L. (Diptera: Muscidae).

from pubmed: horse by Khan HA, Shad SA, Akram W

Effect of livestock manures on the fitness of house fly, Musca domestica L. (Diptera: Muscidae).

Parasitol Res. 2012 May 11;

Authors: Khan HA, Shad SA, Akram W

The house fly, Musca domestica L. (Diptera: Muscidae) is one of the major pests of confined and pastured livestock worldwide. Livestock manures play an important role in the development and spread of M. domestica. In the present study, we investigated the impact of different livestock manures on the fitness and relative growth rate of M. domestica and intrinsic rate of natural increase. We tested the hypotheses by studying life history parameters including developmental time from egg to adult’s eclosion, fecundity, longevity, and survival on manures of buffalo, cow, nursing calf, dog, horse, poultry, sheep, and goat, which revealed significant differences that might be associated with fitness costs. The maggots reared on poultry manure developed faster compared to any other host manure. The total developmental time was the shortest on poultry manure and the longest on horse manure. The fecundity by females reared on poultry, nursing calf, and dog manures was greater than on any other host manures. Similarly, percent survival of immature stages, pupal weight, eggs viability, adults’ eclosion, survival and longevity, intrinsic rate of natural increase, and biotic potential were significantly higher on poultry, nursing calf, and dog manures compared to any other livestock manures tested. However, the sex ratio of adult flies remained the same on all types of manures. The low survival on horse, buffalo, cow, sheep, and goat manures suggest unsuitability of these manures, while the higher pupal weight on poultry, nursing calf, and dog manures suggest that these may provide better food quality to M. domestica compared with any other host manures. Our results point to the role of livestock manures in increasing local M. domestica populations. Such results could help to design cultural management strategies which may include sanitation, moisture management, and manure removal.

PMID: 22576856 [PubMed – as supplied by publisher]



Comment:  Finally, the horse is exonerated as the major cause of fly production!  This abstract gives good thought to manure management and whether chickens are worth having around, given the differential of fly generation.

Dewormer comparisons – generic vs conventional.

Comparative performance of macrocyclic lactones against large strongyles in horses.

from pubmed: horse by Toscan G, Cezar AS, Pereira RC, Silva GB, Sangioni LA, Oliveira LS, Vogel FS

Comparative performance of macrocyclic lactones against large strongyles in horses.

Parasitol Int. 2012 May 8;

Authors: Toscan G, Cezar AS, Pereira RC, Silva GB, Sangioni LA, Oliveira LS, Vogel FS

Several formulations of macrocyclic lactones (abamectin, ivermectin, moxidectin), including ivermectin combined with pyrantel (tetrahydropyrimidine) and ivermectin combined with praziquantel (pyrazinoisoquinolin derivative), were tested regarding their efficacy to control gastrointestinal nematodes of horses on a stud farm in southern Brazil. In addition, we tested a pharmaceutically produced generic paste containing ivermectin 4%. Similar formulations of avermectins had different efficacies measured by reduction of EPG. Levels of efficacy of the tested drugs varied against Strongylus edentatus, S. equinus and S. vulgaris. The generic paste (ivermectin 4%) was less effective than the conventional drugs.

PMID: 22580448 [PubMed – as supplied by publisher



Comment:  Brand name dewormers are recommended over generic, inexpensive versions.  This study illustrates the potential outcome and difference between these two formulations.

Electrolyte Supplementation in the Horse – is it effective?? Find comments after the abstract.

Gastric emptying and intestinal absorption of electrolytes,and exercise performance in electrolyte supplemented horses.

via pubmed: horse by Lindinger MI, Ecker GL on 5/17/12

Gastric emptying and intestinal absorption of electrolytes,and exercise performance in electrolyte supplemented horses.

Exp Physiol. 2012 May 11;

Authors: Lindinger MI, Ecker GL

Horses lose considerably more electrolytes through sweating during prolonged exercise than can be readily replaced through feeds. The present study tested an oral electrolyte supplement (ES) designed to replace sweat electrolyte losses. We measured gastric emptying of 3L of ES (using gamma imaging of 99Tc- sulfide colloid), the absorption of Na+ and K+ from the g.i. tract using 24Na+ and 42K+, and the distribution of these ions in the body by measuring radioactivity within plasma and sweat during exercise. Three L of ES emptied from the stomach as fast as water, with a half time of 47 minutes, and appeared in plasma by 10 minutes after administration (n = 4 horses). Peak values of plasma 24Na+ and 42K+ radioactivity occurred at 20-40 minutes and a more rapid disappearance of K+ radioactivity from plasma was indicative of movement of K+ into cells (n = 3 horses). In a randomized crossover experiment (n = 4 horses), 1h after administration of placebo (water), 1 L or 3 L of ES containing 24Na+, horses exercised on a treadmill at 30% of peak VO2 until voluntary fatigue. 24Na+ appeared in sweat at 10 minutes of exercise, and when horses received 3L of ES the duration to voluntary fatigue was increased in all horses by 33+10 %. It is concluded that an oral ES designed to replace sweat ion losses was rapidly emptied from the g.i. tract, was rapidly absorbed in the upper intestinal tract and rapidly distributed within the body. The ES clearly served as a reservoir to replace sweat ion losses during exercise, and administration of ES prior to exercise resulted in increased duration of submaximal exercise.

PMID: 22581743 [PubMed – as supplied by publisher]



Electrolyte supplementation has been effectively used for many years in the equine sport of endurance riding and racing.  Though feeds provide the primary source, maximal exercise and sweating can create a substantial deficit in electrolytes, leading to possible gastrointestinal and muscle issues.  Any sport or circumstance that causes significant sweating deserves attention for possible supplementation.