Veterinary external parasites; life cycle, effect, treatment, and control

25/03/2023

Ear mites
Ear mite basics

Ear mites are common in young cats and dogs, and generally confine themselves to the ears and surrounding area. Mites are tiny and individual mites may be seen only with the aid of a microscope. Your pet can pick up ear mites by close contact with an infested pet or its bedding.

Diagnosis, risks, and consequences

Ear mites can cause intense irritation of the ear canal. Signs of ear mite infestation include excessive head shaking and scratching of the ears. Your pet may scratch to the point that he/she creates bleeding sores around his/her ears. Excessive scratching can also cause breakage of blood vessels in the earflap, causing the formation of a pocket of blood (an aural hematoma) that may require surgery. A brown or black ear discharge is common with ear mite infections, and secondary infections with bacteria or yeast can occur. A swab of the discharge is usually examined under a microscope to confirm the presence of ear mites.

Treatment and control

Treatment of ear mites involves thorough ear cleaning and medication. Your veterinarian can recommend an effective treatment plan.

25/03/2023

Ticks
Tick basics

Ticks are commonly found in wooded areas, brush, shrubs and wild undergrowth, and any animal (or human, for that matter) that enters these environments is at risk of becoming a tick’s host. Immature ticks often feed on small, wild animals found in forests, prairies, and brush. Adult ticks seek larger hosts like dogs and cats which venture into these habitats. Tick exposure may be seasonal, depending on geographic location. There are many different species of ticks that can affect dogs and cats.

Ticks are capable of spreading serious infectious diseases.

Diagnosis, risks and consequences

Ticks are most often found around your dog’s neck, in the ears, in the folds between the legs and the body, and between the toes, but they can be found anywhere on the body and are usually easily seen or felt. Cats may have ticks on their neck or face. Tick bites can cause skin irritation and heavy infestations can cause anemia in pets. An adult female tick can ingest up to 100 times her weight in blood! Ticks are capable of spreading serious infectious diseases (such as Lyme disease, Rocky Mountain Spotted Fever, and others) to the pets and the people on which they feed. They can also cause tick paralysis. Disease risk varies by geographic area and tick species.

Treatment and control

Prompt removal of ticks is very important because it lessens the chance of disease transmission from the tick to your pet. Remove ticks by carefully using tweezers to firmly grip the tick as close to the pet’s skin as possible and gently and steadily pulling the tick free without twisting it or crushing the tick during removal. Crushing, twisting or jerking the tick out of the skin while its head is still buried could result in leaving the tick’s mouth parts in your pet’s skin; this can cause a reaction and may become infected. After removing the tick, crush it while avoiding contact with tick fluids that can carry disease. Do not attempt to smother the tick with alcohol or petroleum jelly, or apply a hot match to it, as this may cause the tick to regurgitate saliva into the wound and increase the risk of disease if the tick is infected.

Pets at risk for ticks should be treated during the tick season with an appropriate preventive. Your veterinarian can recommend a product best suited to your pet’s needs. Owners who take their pets to tick-prone areas during camping, sporting, or hiking trips should examine their pets for ticks immediately upon returning home and remove them from their pets. If your pet picks up ticks in your backyard, trimming bushes and removing brush may reduce your pet’s exposure and risk of infestation. And, if you find ticks on your pet, don’t forget to check yourself for ticks, too!

25/03/2023

Fleas
dog scratching
Fleas thrive when the weather is warm and humid. Depending on your climate, fleas may be a seasonal or year-round problem. Your pet can pick up fleas wherever an infestation exists, often in areas frequented by other cats and dogs. Adult fleas are dark brown, no bigger than a sesame seed, and able to move rapidly over your pet’s skin.

Once the flea becomes an adult, it spends virtually all of its time on your pet. Female fleas begin laying eggs within 24 hours of selecting your pet as a host, producing up to 50 eggs each day. These eggs fall from your pet onto the floor or furniture, including your pet’s bed, or onto any other indoor or outdoor area where your pet happens to go. Tiny, worm-like larvae hatch from the eggs and burrow into carpets, under furniture, or into soil before spinning a cocoon. The cocooned flea pupae can lie dormant (inactive) for weeks before emerging as adults that are ready to infest (or re-infest) your pet. The result is a flea life cycle of anywhere from 12 days to 6 months, depending on environmental factors such as temperature and humidity.

Diagnosis, risks and consequences

You may not know that your pet has fleas until their number increases to the point that your pet is obviously uncomfortable. Signs of flea problems range from mild redness to severe scratching that can lead to open sores and skin infections (“hot spots”). One of the first things you may notice on a pet with fleas is “flea dirt”—the black flea droppings left on your pet’s coat. You may not actually see the fleas themselves, but they can still be on your pet and in the environment.

Fleas bite animals and suck their blood; young or small pets with heavy flea infestations may become anemic. Some pets can develop an allergy to flea saliva that may result in more severe irritation and scratching; these pets can become severely itchy from just one or two flea bites. Also, pets can become infected with certain types of tapeworms if they ingest fleas carrying tapeworm eggs (a pet using its teeth to scratch the flea bites often eats the fleas). In areas with moderate to severe flea infestations, people may also be bitten by fleas. While fleas are capable of transmitting several infectious diseases to pets and people, this is rare.

Treatment and control

Your veterinarian will recommend an appropriate flea control plan for your pet based on your needs, your pet’s needs and the severity of the flea infestation.

Pets at risk for fleas should be treated during the flea season with an appropriate preventive. Your veterinarian can recommend a product most suitable for your pet.

Your veterinarian will recommend an appropriate flea control plan for your pet based on your needs, your pet’s needs and the severity of the flea infestation.

Because much of the flea’s life cycle is spent off of your pet, treating only your pet will not eliminate the problem. If you kill the adult fleas and do not kill the eggs, larvae and pupae, your pet will become re-infested when these fleas become adults and the cycle will start all over again. Therefore, in addition to treating your pet, reduce the flea population in your house by thoroughly cleaning your pet’s sleeping quarters and vacuuming floors and furniture that your pet comes in contact with frequently. Careful and regular vacuuming/cleaning of the pet’s living area helps to remove and kill flea eggs, larvae, and pupae.

You may be advised to treat your house with insecticides to kill the fleas; consult with your veterinarian about products safe for use around pets and children. Flea larvae are more resistant than adult fleas to insecticides. With moderate and severe flea infestations, you may also be advised to treat your yard. Your veterinarian can recommend an appropriate course of action and suggest ways

02/10/2022

Dairy cattle
As in beef cattle, the overarching theme for the prevention strategy of parasitic infection is to reduce the animals’ exposure to parasites and their infectious forms. Because multiple animals will be exposed, any strategy will focus on entire groups of animals rather than individuals. So far, this is similar to prevention strategies for any other infectious diseases on farm. However, when thinking about the prevention of parasite infections on farm, the veterinarian must be aware of the infectious form of the parasite (for example, eggs versus larvae) and whether or not other hosts are involved in the life cycle. Then the best parasiticide is selected and management practices, such as grazing schedule, are properly timed to avoid exposure to infectious parasite forms in the environment. In most cases, prevention strategies therefore boil down to good on-farm hygiene and use of well-timed and correctly selected dewormers, as well as pasture management as described for beef cattle. There are different forms of deworming medications for dairy cattle. For simplicity of application, many are pour-ons or feed additives; some are injectables. Oral pastes or any formulation that requires you to handle the animals’ heads is rarely used because it is labor-intensive. Any product used in an animal that may be used for milk or meat has a specific withdrawal time. Withdrawal time is defined as the period from when the drug was used until the milk may be put in the bulk tank or the animal sent to slaughter for meat. How long the withdrawal time is and whether you can use a given drug in a lactating cow depends on the product. One thing that people might not be aware of – once a cow has calved for the first time, she is always considered to be a lactating animal, even if she’s not being milked (dry period). Always, always, read the label to know what the product will treat for, at what dosage and frequency it should be used, by what route it should be administered, what class of animals it is for, and withdrawal times.

02/10/2022

Insecticide sprays and pour-ons are effective for many different external parasites but have the drawback of increased animal handling costs and stress during the fly-season. Insecticide sprays are the only way to manage adult stable flies. Ear tags impregnated with insecticide can be effective in fly control. Maximizing control requires two tags per animal, and timing of application with peak fly numbers often requires a separate handling session of the animals. Ear tags provide good face fly control if applied properly.
Larvicides prevent fly larvae from developing in to adults and are administered through free choice mineral. To be effective cattle must consume an adequate amount and not be in the proximity of untreated cattle
Injectable products and pour-ons with systemic activity are mainly the macrocyclic lactones. These are effective against some flies as well as mites and lice. For mites and lice a second treatment may be needed in two to three weeks to kill newly hatched parasites unless using an extended duration product.
Sanitation or cleaning up of wasted feed or manure that serve as egg-laying sites for certain flies can greatly contribute to the control of certain flies locally. In addition, egg laying sites may be treated with a larvicide.
Environmental management may be a key component to tick control. The reduction of brushy areas and thick wooded areas reduces the habitat for the ticks and reduces exposure.
Certain native parasitic wasps are used as biological control agents of fly populations. Currently, farmers can buy parasitic wasps from commercial insectaries. These wasps emerge into adulthood from the pupal stage, where they develop wings. They fly from the release stations in which they have been held, hung from barn ceilings or other out-of-reach places. The wasps only target flies in their pupal stage. When the wasp finds a pupa in soil or litter, she inserts her stinger and withdraws it, drawing blood and paralyzing the pupa and inserting one egg. The egg hatches after 1 day, and the larva feeds on body fluids and organs for 2-4 weeks. Eventually, the wasp chews its way out of the dead host’s puparium and flies away as an adult.

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