Red mites : can transmit diseases & tips for prevention and monitoring.

Red mites are small parasites of about one millimeter.
They cause a lot of nuisance in the hen house, and can also transmit diseases and weaken a chicken severely. Sometimes if the owner doesn’t see the red mites before the infestation gets bad, chicks and chickens can get killed by herds of red mite. Red mites, are also called red roost mites and bird mites.
The latin name is Dermanyssus gallinae.

Good to know
The life cycle of red mites knows tree stages: mite-egg, larvae, adult
The red mites die in freezing colds, and die in winter in many climates, but the mite-eggs don’t. Temps over 50C kill all stages, including the mite-eggs.
Red mites hate bright daylight and like to hide in cracks during the day.

Red mites transmit diseases
(From Editorial team Levende Have / Pluimveeweb.nl and translated from Dutch by Google.)

The red mites, appear to be able to carry the fowlpox virus and infect the poultry with it.

Dr. Paul Overgaauw, parasitologist and researcher at Utrecht University, has experimentally infected bird mites. The number of transmissible viruses is limited to the fowlpox virus, but several types have been found to be contagious among the bacteria.

An experimental study in the barn showed that mites can carry Salmonella bacteria and transmit them through blood or skin contact. It also turned out that afterwards the eggs and offspring of the mites were infected with Salmonella. Bird mites can also carry the bacterium Pasteurella multocida which causes pasteurellosis (bird cholera). The bacterium E. Rhusiopathiae has also been shown to cause spot disease which causes skin inflammation in humans and which, in addition to skin problems, can lead to very high losses in chickens. Finally, the bacteria that cause Q fever and Lyme disease have been found in bird mites. The bird mite can play a role in the spread of these diseases, but more research is needed to determine this more accurately, says Paul Overgaauw on Pluimveeweb.nl

Source: https://www.levendehave.nl/nieuws/bloedluizen-vogelmijten-kunnen-ook-ziektes-overdragen.

How to eliminate a red mites
There are many methods people use to eliminate red mites but if you have a bad infestation it is never easy to eliminate all of them.
Especially when you have a coop with insulation it seems impossible to eliminate all of them. Here is a list with possibilities. I don’t want to pretend to know what is best. But prevention is always better than having to deal with a bad infestation.

Prevention

• Check weekly from spring - autumn. As long as the temp stays above 4*C inside the coop. And at least twice a week when it’s warm and humid.
• Use diatomaceous earth. Add a few spoons of diatomaceous earth in the sand bath (area) . Make a paste you can paint on the inside coop walls. Especially around where the chickens sleep and in the nest boxes. Sprinkle it under the bedding in the nestboxes.
• Make the roost so far away from the walls that the feathers don’t touch the walls.
• Use oil baths to where you attach the roosts to the wall or in the bottom of the coop. Or smear a thick layer of DE ‘paint’ on the roosts and the joint to the wall.
• Don’t let the chickens sleep in a nestbox.
• Don’t buy a second hand coop without knowing for sure.
• Add scenting tabacco or lavender in the coop.
• There are supplements you can buy to add to feed and water. The supplements make the blood of the chickens disgusting for the red mites.

Helping in prevention

• Use no bedding but sand on the coop floor (mixed with a little DE) in spring and summer.
• Make a large window near the roost area because mites flee to dark corners as soon as it gets light.
• Make lots of ventilation in the roost area to keep the temperature a bit lower during the summer.

Eliminate
The methods I came across:

• Cleaning with all kind of soaps / detergents
• Smearing oil /oily or fatty substances on the inside of the coop
• Steaming
• Poisoning the mites
• Natural poisons that break down to kill the mites
• Natural enemies
• Carefully heating the surface with a burner.
• Burning the surfaces or the whole coop and build of buy a new one.

Monitoring

• Red mite love to hide in corrugated cardboard. To spot red mite it’s best to use white corrugated paper. Make rolls from biscuits paper and attach them under the roosts with an elastic band or tie wraps. Check every week in spring and autumn, and twice every week in summer when the air is warm and moist. Make tie wraps loose so you can get the roll out and in again easily. If you spot any red mites, put the rolls in the microwave for 20 sec, to kill all mites and eggs inside. If you have a broody or chicks, lay some rolls in the nestboxes too.
• Checking at night: use a flashlight and shine on the chickens when its dark to see if anything is moving on the roosts/chickens.
• Wrap corrugated cardboard strips 3 - 4 times around the ends of the roost during the day with a piece of tape. Unfold them the next morning and see if you find any mites. Do this weekly/twice a week to monitor (as with the biscuits paper rolls). If you have mites you can use this method to catch mites too. Make sure the mites are dead if you want to reuse the corrugated cardboard strips.