The hazards of late summer: sharp-ended grass seeds and harvest mites. Podcast from Pete the Vet on Newstalk’s Pat Kenny Show

In this week’s podcast, I talk about two common hazards of the late summer for pets: grass seeds and harvest mites. To listen click on the play button below.

Grass seeds

Grass seeds seem like innocuous little objects, but they are designed in such a way that they regularly cause problems for animals. They have a sharp fibrous tip; it feels like a pinprick if you press it against the back of your hand. This tip is sharp enough to puncture soft skin, and that’s exactly what happens to animals.
Soft, thin skin is most vulnerable: the area between the toes, on the underside of the foot is the main area that’s affected.
As well as the sharp tip, grass seeds have a fibrous sheath that includes barb-like bristles. This means that they can only move forwards in the same direction that they have penetrated a surface: the barbs prevent them from moving backwards, out of the skin. So once a grass seed has punctured the skin, it tends to drive deeper and deeper.
One of the challenges is that these can be difficult to diagnose: the seed can puncture the skin then disappear from view, leaving an invisible pinpoint hole. Then with time, the seed causes irritation under the surface. Sometimes there are very few signs of illness: one recent case was presented with nothing more than sudden onset excessive panting. It was only a few days later that the presence of the seed became apparent, when the dog started limping and licking at the foot, and on close examination, the seed could be found and removed.
Grass seeds don’t just cause problems with the feet: they can also affect several other parts of the body, causing a double problem: they irritate the animal, as well as carrying bacterial infection into the body.
Sore ears are another possible problem: in these cases, the grass seed doesn’t even need to penetrate the surface of the body. The grass seed enters the opening of the ear while the dog is running through a meadow. Then due to its barbed outer surface, it steadily moves down the ear canal, until eventually it reaches the bottom, where it sits, pressed against the ear drum. This causes intense discomfort, with the dog vigorously scratching and rubbing at the ear. Affected dogs need to be taken to the vet for the grass seed to be removed carefully, usually under sedation.
Grass seeds are also prone to penetrating the lining of the digestive tract when dogs eat grass. They can puncture the oral cavity, the gullet, the stomach or intestines. They can then migrate through the animal’s insides, causing pain and swelling wherever they end up. These cases can be baffling, with animals becoming unwell and the cause being difficult to find. Vets need to use all of their skills and diagnostic tests to track them down, even going as far as MRI scans in some cases.
Pet owners should never underestimate the disease-causing ability of the humble grass seed.

Harvest mites.

These tiny creepy crawlies (1-2mm diameter) are present all over Ireland in the late summer every year, with the parasites lurking in meadows and scrubby land, hiding in grass and other vegetation. They wait for passing warm-blooded animals, and then attach themselves to the closest part of the animals’ body – usually the feet or lower legs. After the mites grab hold of the animal with their spidery legs, they crawl into a secure part of the animal’s body, sticking themselves to the underside of dogs, cats and wild animals. They remain attached for several days, feeding on the skin of their host, before falling off back into the field to complete their life cycle.
Typically, harvest mites cause itchiness of the feet, between the toes, but they can also affect other parts of the body such as armpits, groin and ears.
Not all pets are badly affected by harvest mites: the worst problems happen when an animal develops an allergy to them that a problem. Many dogs and cats have harvest mites present with no visible sign of itchiness or bother.
Most other parasites, like fleas, occur all year round, with peaks and troughs during different months. Harvest mites are much more specific about their timing. They emerge in late August and September, and by early October, they vanish.
When pets get itchy at this time of year, harvest mites are a common cause. As a vet, I know to check between the toes and on the underside of the body: the pin-point, orange mites are easy to spot.
They can be treated with spray-on insecticides but they are difficult to remove: the best answer is to try to avoid areas where they are common, and to give anti-inflammatory medication to animals that suffer a severe itchy reaction to them.

Question about pets from owners


  1. My cat was at the vet and they de-fleaed him, but he still has a big rash on his belly. He is very uncomfortable. What can we do to help him?


To watch Pete doing his weekly Facebook Live video session ,see here .

To listen to the podcast, click on the play button below.

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