Rising mosquito exercise heading into the summer time months poses an elevated danger of transmitting heartworm illness to dogs, which might result in harm of the center, lungs and arteries if left untreated.
Cathy Campbell, DVM, veterinary diagnostician on the Texas A&M Veterinary Medical Diagnostic Laboratory, TVMDL, in Bryan-College Station, explains the heartworm life cycle, the very best time for testing, and suggestions for prevention.
What are heartworms and the way are they transmitted to dogs?
Heartworm illness is attributable to the parasitic worm Dirofilaria immitis and is transmitted to animals by mosquitoes, in line with the American Heartworm Society. Mature heartworms can dwell inside dogs for as much as seven years.
“When a mosquito happens to bite an animal infected with heartworms, it ingests microfilariae, or baby heartworms, through a blood meal,” Campbell stated.
Those microfilariae morph into larvae contained in the mosquito in 10-14 days. That contaminated mosquito tends to fly round and chew a canine, transmitting the larvae to a brand new host. Once transmitted, the larvae enter the canine’s bloodstream and migrate to the center.
“Larvae set up housekeeping in the heart and grow into sexual maturity in six to seven months,” Campbell stated. “Mature worms produce microfilariae, which are released into the bloodstream where they await another mosquito to come and bite the dog, take up a blood sample and continue the cycle.”
It takes six to seven months within the heartworm’s life cycle earlier than they are often detected on a check. Therefore, most veterinarians advocate testing dogs for heartworms round 6 to 7 months of age.
Testing to detect heartworms in dogs
TVMDL presents two totally different approaches to testing.
The first method is to detect the child heartworms produced by grownup heartworms within the coronary heart. TVMDL’s medical pathology part can detect microfilariae utilizing both a filter methodology or by a modified Knott’s check.
However, not all heartworm infections produce child heartworms, so it’s best to incorporate an “occult” heartworm check utilizing an enzyme-linked immunosorbent assay, ELISA — the second testing method.
Technicians at TVMDL use the ELISA check to detect antigens related to pregnant feminine heartworms. A optimistic consequence signifies grownup feminine heartworms are current. This is the first testing methodology to detect heartworms.
TVMDL’s function in testing for heartworm illness
Most non-public veterinary clinics can carry out heartworm antigen/ELISA testing in-house, Campbell stated. TVMDL primarily conducts confirmatory heartworm testing with a distinct antigen check after these clinics have gotten an preliminary optimistic consequence.
Confirmatory testing is carried out for a number of causes. The first is to verify a canine really is optimistic for heartworms previous to present process remedy, as a result of the remedy drug used for heartworms can have important negative effects and shouldn’t be used except grownup heartworms are current.
The second purpose is to doc heartworm prevention drug failure. Several producers guarantee protection of remedy for a canine that has been on their product however developed heartworms regardless of well-documented testing and dishing out of remedy by a licensed veterinarian. There is proof of a preventative-resistant heartworm variant, primarily within the Mississippi delta area of the U.S.
Lastly, typically check outcomes will be unclear. TVMDL can supply a differing testing possibility to assist help or verify findings.
Although TVMDL serves a confirmatory function for many antigen heartworm checks, the company usually conducts preliminary testing for the heartworm antibody check in felines. Due to the infrequency with which this check is required in non-public observe on cats, many veterinary clinics don’t carry out this check in-house and defer testing to TVMDL.
Prevention suggestions
TVMDL encourages veterinarians to teach their shoppers on the advantages of giving year-round heartworm preventatives to each their canine and feline sufferers and helps annual testing of canines.
“Texas’ mild climate lends toward year-round mosquito activity,” Campbell stated. “Missing a dose of heartworm preventative, or even administering a dose late, may allow a window of opportunity for mosquitoes to infect pets.”
For extra info on heartworm illness, go to the American Heartworm Society. For extra info on testing, go to TVMDL’s testing services or name the TVMDL laboratory nearest to you.
