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A note from Dr. Strubberg

Asian Longhorned Tick

In late 2017, the USDA’s National Veterinary Services Laboratories (NVSL) confirmed the presence of the Asian longhorned tick (Haemaphysalis longicornis) in the United States. The Asian longhorned tick is not native to the United States, but is a serious threat to livestock in Australia, New Zealand and countries in eastern Asia. After the initial finding, animal health officials began exploring how and when the tick arrived in the U.S. They hypothesize the tick entered the country via domestic pets (e.g. dogs), horses, livestock or humans.

In July 2021, the Asian longhorned tick was first identified in Missouri. There have been three identifications in Missouri since then. Asian longhorned ticks have been found in 17 states since 2017.

Why are state and federal agencies concerned?

This tick is known to infest a wide range of species including North American wildlife species, humans, dogs, cats and livestock. The tick can attach itself to these warm-blooded animals to feed. If too many ticks attach to one animal, the loss of blood can kill the animal. In other countries, the Asian longhorned tick can transmit the agent of bovine theileriosis to cattle and babesiosis to several domestic animal species. Although we have not seen it carry these diseases in the U.S., animal health authorities continue to monitor it closely.

What are state and federal agencies doing?

State agencies, in collaboration with USDA-APHIS and the CDC, will continue tick collection and identification throughout Missouri and states across the country. Federal agencies and animal health professionals will continue to monitor wildlife, livestock and horses in local areas for these ticks. The primary goal is to prevent the spread of the Asian longhorn tick throughout the U.S.

What do Longhorned Ticks look like?

The adult longhorned tick is light brown in color and grows to the size of a pea when it is full of blood. The other life stages of the tick are very small and difficult to see with the naked eye.

Longhorned tick lifecycle images.  Engorged female (left), partially engorged female (center) and engorged larvae (right)

Pictured above are (left) engorged female, (center) partially engorged female and (right) engorged larvae.

Photo courtesy of James L. Occi, Rutgers University

What can you do to help

Collect suspected longhorn ticks and send them to NVSL using the Parasite Submission Form.
Call the NVSL Lab at (515) 337-7514 with questions.

  1. Collect any suspicious ticks (for official identification)
  2. Place the tick in a leak proof container (Preserve in isopropyl alcohol)
  3. Mail ticks to:
    National Veterinary Services Lab
    1920 Dayton Avenue
    Ames, IA 50010

Asian Longhorned Tick Info Sheet

Veterinary Resources

Swine Barn

Livestock Import Requirements & Entry Permits
Review import regulations and 24-hour access to online permitting.

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Health Certificate Resources
CVI options for Missouri Veterinarians

Animal Diagnostic Lab

Animal Diagnostic Labs
Laboratories offer a variety of diagnostic services. Please contact your nearest laboratory for more information.

Emerging Issues

We want Missouri veterinarians and horse owners to be aware of some equine diseases detected in Missouri recently. Equine Infectious Anemia has been detected in 4 Missouri counties during 2021 and 2022. These detections were made by personal and market veterinarians. Confirmatory testing was done at the National Veterinary Services Lab (NVSL). The infected horses have been euthanized. The affected herds were quarantined and tested multiple times over the following few months. In total, 11 horses were detected and euthanized during these investigations. It is suspected that nearly all cases in the US during recent years are due to iatrogenic spread with shared needles. Frequently, the horses are implicated to have participated in unsanctioned racing. The Missouri Department of Agriculture strongly encourages regular Coggins testing. The above cases could have been detected sooner and sometimes prevented if required testing had been done.

West Nile Virus infection has been diagnosed in at least 8 horses in 7 Missouri counties during 2022. These horses have displayed clinical neurologic symptoms. Some have been reported to have survived. These cases have been reported by private veterinarians after testing at private and University labs. NVSL follows up with confirmatory testing of those submitted samples. West Nile vaccine is available for horses and is commonly recommended.

Avian Influenza

Avian influenza (AI) is caused by an influenza type A virus which can infect poultry (such as chickens, turkeys, pheasants, quail, domestic ducks, geese, and guinea fowl) and wild birds (especially waterfowl).

AI viruses are classified by a combination of two groups of proteins: hemagglutinin or “H” proteins, of which there are 16 (H1–H16), and neuraminidase or “N” proteins, of which there are 9 (N1–N9). AI viruses are further classified by their pathogenicity—the ability of a particular virus strain to produce disease in domestic chickens.

Highly Pathogenic Avian Influenza (HPAI) is a serious disease and requires rapid response because it is highly contagious and often fatal to chickens. The goal is to quickly contain and eradicate the disease, protecting our poultry industry, and in turn, the American consumer.

Due to the Avian Influenza response, please submit a permit request form in order to move poultry within control zones.

Low pathogenicity avian influenza (LPAI) viruses typically cause little or no clinical signs in infected poultry. The LPAI virus is excreted through infected birds’ feces and respiratory secretions. It spreads primarily through direct contact between healthy and infected birds. It can also be spread through indirect contact with contaminated equipment and materials. Low pathogenicity avian influenza (LPAI) virus strains occur naturally in wild migratory waterfowl and shorebirds without causing illness.

Biosecurity is key in prevention of avian influenza.

Here are a few biosecurity steps that can be implemented when working with birds or owning your own birds:

  • Minimum PPE such as eye protection, gloves, and disposable boot covers or rubber boots that can be disinfected should be worn when working with possibly diseased livestock or poultry. Coveralls and masks are recommended.
  • Don’t haul disease home. Keep work clothes and shoes separate for home clothes and shoes. If working with sick birds on location, clean and disinfect the vehicle and equipment used on that premises before going to another premises or home.
  • Keep it clean-wash hands before and after handling poultry, clean and disinfect equipment and shoes before visiting another place or before working with your own livestock and poultry.

Equine Infectious Anemia (EIA)

Equine Infectious Anemia is an acute or chronic viral disease of equidae. The virus is related to the human AIDS Lentivirus, but is not known to infect humans. The predominate means of spread is the intermittent feeding of biting insects, especially horse flies and deer flies. EIA can also be spread through indiscriminate use of hypodermic needles, blood transfusions, and use of contaminated instruments or tack. No specific treatment or vaccine is currently available.

In Missouri, equidae must be tested for EIA when they are involved in a change-of-ownership, when they are imported from another state, when they are publicly exhibited, boarded, trained, bred, and when they are sold through a livestock market. Discovery of disease requires quarantining and retesting of the affected and exposed animal(s). Upon confirmation of positive test results from the USDA National Veterinary Services Laboratory, the affected animal is permanently identified and either euthanized or permanently quarantined to the owner’s premises until natural death occurs.

For further information, please contact the Division of Animal Health at (573) 751-3377, or e-mail Animal.Health@mda.mo.gov.

West Nile Virus

West Nile is a viral disease that usually affects birds, people and horses. It is spread by mosquitoes and is generally seen in Missouri during the mid July thru October time period. The past several years have seen a very low incidence in the Midwest, but this year there have been several cases reported in the surrounding states and two positive horses in Missouri. The horses initially appear depressed and generally develop neurologic signs, such as an inability to stand or a staggering gait, as the disease progresses. Contact your veterinarian immediately if you notice these symptoms in your horses.

Horse owners should consult their veterinarians regarding the best vaccine to use to prevent the disease in your horses. Horses that were vaccinated early in the spring may require a booster in the late summer or fall.

In 2022 Missouri reported 8 cases of West Nile Virus in Missouri spanning 7 counties.

For further information, please contact the Division of Animal Health at (573) 751-3377, or e-mail Animal.Health@mda.mo.gov.

For more information on West Nile Virus or EIA, visit our webpage.

For a full list of reportable diseases, visit our webpage.