animal health

Information About EEE from CVMDL at UConn

mosquito biting a person
2003
CDC/James Gathany
Photographer: James Gathany
This is an Ochlerotatus triseriatus mosquito obtaining a blood meal from a human hand.
Also known as Aedes triseriatus, and commonly known as the ”treehole mosquito”, this species is a known West Nile Virus vector.
Photo by James Gathany, Centers for Disease Control

Eastern Equine Encephalitis (EEE) is a disease caused by a virus that mosquitos transmit. The name of the disease is misleading in that this virus can infect and cause disease in humans and a wide variety of animal species, including birds as well as horses and other equids. Horses that have not been vaccinated for EEE die within days of being infected as there is no treatment. There is an effective equine vaccine for EEE, however not for other species. Researchers and veterinarians UConn’s Connecticut Veterinary Medical Diagnostic Laboratory (CVMDL) encourage equine owners to consider vaccinating their animals, and other animal owners to implement measures to reduce mosquito habitats and thereby potential contact with mosquitos.

Mosquitos that feed on infected wild birds transmit EEE to horses and humans. Once infected, the virus attacks the central nervous system of the host. For horses, disease signs usually appear within five days and the clinical signs include fever, a dull or sleepy appearance, muscle twitches, and a weak staggering gait. Fatality in horses is 90% or higher as horses often go down and are unable to stand again, and those that do survive may have permanent brain damage.

EEE is transmitted by two main types of mosquito vectors; the primary vector and the bridging vector. Culiseta melanura, the primary vector which feeds almost exclusively on birds, serves to amplify and maintain the virus within wild bird populations. Other mosquito species, which indiscriminatingly feed on birds, horses, and humans, serve as the bridging vector capable of transmitting EEE from wildlife to horses and humans.

With the location of horse barns and pastures in rural areas the animals have increased exposure to mosquitos. Horses cannot pass EEE to humans, or to other horses, and are therefore referred to as a dead-end host. If an infected mosquito bites a human, that person can be infected and may develop disease. According to the Center for Disease Control, illness in humans due to EEE is rare, but when disease develops, it is serious.

Proactive steps can be taken to prevent EEE virus infection in humans and horses. A vaccine is available for horses, talk to your veterinarian about vaccinating annually for EEE. Mosquito control techniques include eliminating standing water, cleaning water troughs weekly, avoiding mosquito-infested areas, and using insect repellent.

CVMDL, part of the Department of Pathobiology in UConn’s College of Agriculture, Health and Natural Resources, is on the frontlines of research and testing to keep humans and animals safe. For more information visit http://cvmdl.uconn.edu or call 860-486-3738.

 

Reference

LSU Ag Center Research and Extension: http://www.lmca.us/PDF/pub2834eee.pdf

Ewe Nutrition Leads to Lamb Health

lambs in the barn at UConn
Photo: UConn

Lambing season rolls around every spring, and with it comes night lamb checks, fuzzy little faces bleating for mama, and hopefully, healthy ewes and lambs. But ensuring that those lambs and ewes are healthy at birth starts long before lambing occurs.

Our research group focuses on how the ewe’s diet while she is pregnant affects the growth and development of her lambs. When a ewe is provided excess or restricted nutrition during pregnancy, it affects her ability to support the proper development of her lambs. This is compounded when ewes carry larger litter sizes (2 or more lambs). Development of the lambs during gestation prepares those animals for growth after lambing. Ewes that are over- or under-fed during pregnancy produce lambs that ultimately end up with more fat and less muscle. This is undesirable because there is less meat produced and the animals are less healthy due to increased body fat. Further, lambs from poorly nourished ewes tend to have more connective tissue, resulting in tougher cuts of meat. But there are strategies that producers can easily employ to improve the health and productivity of their flocks.

Transabdominal ultrasound during early pregnancy (around day 30) can be performed with the ewe in the standing position, with little stress to the animal, and in less than 5 minutes per animal by a skilled technician. Ultrasound can provide critical information, such as how many lambs a ewe is carrying and, when appropriate fetal measurements (such as the length from the crown to the rump) are taken, an estimated due date can be calculated. Ewes with larger litter sizes require additional feed, but are also at greater risk for ketosis in late gestation. Identifying the number of offspring early will allow farmers to prevent complications during and after pregnancy.

Once litter size and estimated lambing date are known, flock managers can appropriately feed their ewes according to litter size and stage of gestation. Best practice suggests that ewes should be separated by litter size so that those carrying larger litters can be fed greater quantities of food. This prevents over-feeding ewes that are pregnant with singletons and under-feeding ewes that are pregnant with multiples. Ewes should be fed based on their stage of gestation (early-, mid-, late-), and the number of lambs they are carrying. Importantly, body condition should be monitored throughout gestation to ensure that ewes are carrying sufficient condition into lactation, so that they will be able to support their lambs after parturition. To ensure that the feed provided is appropriate, hay and grain analyses can provide flock managers with the nutrient content of their feedstuffs. Nutritional value can vary widely so it is recommended that each load of feed is analyzed. Feed analysis can be easily completed at several labs at relatively low cost. Determining how much feed to provide is based on nutrient requirements published by the National Research Council (https://www.nap.edu/read/11654/). There are also many online feed calculators available for sheep (https://www.sheepandgoat.com/rationsoftware).

Separating ewes by litter size also allows for closer monitoring of ewes with larger litter sizes that are predisposed to ketosis in late gestation. Ketosis is a common metabolic disorder that occurs during periods of extreme energy demands coupled with an inability to meet those demands. In ewes, this occurs most frequently during late gestation when lamb growth is the greatest. At-risk ewes can be monitored during the last four weeks of gestation for ketosis using a hand-held beta-hydroxybutyrate (BHBA) meter. Concentrations between 0.8 to 1.5 mmol/L are considered subclinical and indicate the need for close monitoring until parturition. Blood concentrations of BHBA greater than 1.6 mmol/L are considered indicative of clinical ketosis and would require veterinary attention.

Beyond understanding the effects of poor maternal nutrition during gestation on lambs, our research helps us understand how human babies who are born to over- or under-nourished mothers may be affected. Sheep are excellent models for human health research, as they have similar numbers of offspring and lambs are approximately the same weight at birth as babies. While there are certainly differences in human and sheep physiology, understanding how a mother’s diet influences her offspring’s growth and metabolism benefits both species. By improving ewe health and nutrition during pregnancy, producers will have better growing lambs with improved carcass characteristics. Improving mom’s health and nutrition during pregnancy will decrease the risk of her baby developing metabolic diseases such as diabetes later in life.

For more information on our research, please visit the Fetal Programming Research Group’s website: https://fprg.research.uconn.edu/.

Article by Sarah Reed, PhD, Associate Professor, Department of Animal Science

Robotic Conference at UConn

dairy cow coming out of milking parlor

Register by Friday, October 19th to attend the Robotic Milking Conference at UConn. The day-long event will cover the impacts on animal health, welfare, and economic sustainability for Northeast dairy farms. Admission is $40 per person and $20 for students. For more information and to register visit s.uconn.edu/roboticmilking

Salmonella Awareness is Key to Good Health

CVMDL staff member Jennifer Sale works on equine serum samples for Lyme disease testing.
CVMDL staff member Jennifer Sale works in the lab. Photo: Naturally.UConn.edu

Salmonella are bacteria that can live in the intestinal tracts of animals. There are many different types of salmonellae, some are found solely in animals and others can cause disease in both animals and people. Salmonellosis in humans can occur if they consume foods contaminated with Salmonella or have contact with animals or their environment. Animals commonly found with salmonella include reptiles, amphibians, poultry, wild birds, rodents, pocket pets, farm animals, dogs, cats, and horses.

Animals may carry certain types of Salmonella bacteria without showing any clinical signs of disease. When the Salmonella type does present with clinical signs, septicemia or typhoid, and enteritis (diarrhea) are seen. In some cases, abortion, arthritis, respiratory disease, necrosis of extremities (gangrene), or meningitis may develop. In these severe clinical infections veterinary management of Salmonella infection in an animal or herd may include isolation of the sick animal to recover, and limit any spread within the herd, or to humans. The presence of Salmonella in animals (i.e. Salmonella pullorum-typhoid or Salmonella enteritidis), is reportable to the state veterinarian and actively monitored for through surveillance testing of poultry going to fairs and requiring imported poultry to come from disease-free breeder flocks.

Salmonella is a major public health concern. There are approximately 40,000 human cases of salmonellosis reported in the United States every year, however the number could be thirty or more times greater, as milder cases may not be diagnosed by physicians or reported by the public.

People can become infected with Salmonella by:

  • Eating foods contaminated with the bacteria, such as beef, poultry, unpasteurized milk, eggs, or vegetables that are not properly handled, prepared and cooked.
  • Food contaminated by an unsanitary food handler during preparation.
  • Direct contact with farm animals or pets (including reptiles, baby chicks, and ducklings), animal feces, or animal environments.
  • Touching contaminated surfaces or objects and then touching their mouth or putting a contaminated object into their mouth.
  • Not washing hands after using the bathroom or changing diapers or touching animals or their environments prior to eating or drinking.
  • Drinking unpasteurized milk or contaminated water.

The Connecticut Veterinary Medical Diagnostic Laboratory (CVMDL) at UConn offers a number of diagnostic procedures and tests to assist veterinarians and animal owners in diagnosing Salmonellosis or other possible diseases. Services available are whole dead animal necropsy evaluations, sample culturing for pathogen identification and antimicrobial sensitivity testing, and screening blood samples for export movement or flock certification.

CVMDL is the only laboratory in New England accredited by the American Association of Veterinary Laboratory Diagnosticians. The laboratory is located on the UConn-Storrs campus and provides diagnostic services, professional expertise, research, and detection of newly emerging diseases. CVMDL collaborates with federal, state, and local agencies to detect and monitor diseases important to animal and human health.

CVMDL is part of the Department of Pathobiology and Veterinary Science (PVS) in the College of Agriculture, Health and Natural Resources (CAHNR) at UConn. For more information, visit cvmdl.uconn.edu or contact 860-486-3738 or CVMDL@uconn.edu. Dr. Mary Jane Lis, the State Veterinarian at the Connecticut Department of Agriculture may be contacted with regard to voluntary and mandated testing requirements at 860-713-2505.