This article is from the WSSF 2007 AFRMA Rat & Mouse Tales news-magazine.

By Carmen Jane Booth, D.V.M., Ph.D.

Mary J. Cameron, Halifax, Co. N.S., CANADA
Q Do rats carry a lot of diseases? And are those diseases contagious to humans and other household pets?

Cindy, e-mail
Q I just purchased a new rat. I have had them in the past. This time though my dad said that he heard on the news that pet rats are carrying a disease that is harmful to children. I was wondering what it was and how worried I need to be. I have a 3 year old and a 10 month old. Please let me know if anyone has heard anything about it.

A To answer the question directly, any animal is capable of carrying one or more infectious agents that are transmissible to humans. The most notable disease are Rabies (Lyssavirus), Plague (Yersinia pestis), and Hantavirus. The list of zoonotic disease that rodents are capable of transmitting is long (see below). However, realistically, most of these come from wild rodents, not domestic rodents bred in captivity and sold at pet stores or through the rat fancy. However, there are exceptions. One important zoonotic disease from rodents is Lymphocytic Choriomeningitis virus (LCMV). This virus is more of a problem in pet hamsters and wild mice than domestic rats or mice. Tragically, a parent purchased a hamster for their child and the hamster was carring LCMV. The parent was killed in a car accident and the organs used for organ donation. The parent was infected with LCMV and some of the transplant patients died from LCMV because of the immune suppressive drugs required by organ transplant. However, this was a very rare and exceptional case www.cdc.gov/mmwr/preview/mmwrhtml/mm54d526a1.htm.

As a veterinarian, I take routine precautions when treating pet rodents or any patient and wash my hands between office appointments. Depending upon the symptoms and clinical history, I may choose to wear a mask and gloves. As an owner, at home I treat our pet rats as pets. I do wash my hand before eating, etc. I do the same with my dogs and cats. In the past, my rats came from the shows. In recent years because of my work, I can’t have conventional rodents so I have adopted weanling or young rats and mice free of the rodent viruses and Mycoplasma.

As a parent, my children were not allowed to handle any of our rats until they were old enough to not hurt them. I have always had dogs, cats, rodents, and have three children. Young children can be rough and harmful to animals and any animal may bite if provoked or hurt. My dogs have always been trained and well behaved, but even their patience was tested when my children were toddlers, and so I used baby gates and a play pen to keep them separated if I could not supervise. When my children were young, the rats were kept in a room with a baby gate so that the children couldn’t enter unless an adult was there to supervise. My daughter asked for her own mice when she was ~4th grade and learned how to be responsible for 6 mice for their entire life span. Now she is 14 and does the majority of husbandry for the three family rats. All three children share in the care of the animals that share our life.

Most of these agents are unlikely to improbable in domestic pet rodents. Some breeders do get their colonies evaluated for disease. However, most of the disease problems in pet rats are related to the bacteria Mycoplasma pulmonis which is not zoonotic to humans but highly contagious to other rodents. Getting rodents from a reputable breeder that has screened their colony for LCMV would be ideal. However, most pet stores and breeders do not screen their animals for any diseases, let alone LCMV. A fecal analysis can rule out some zoonotic parasites. Microbiology can be used to rule out bacterial infection. Serology can be used to rule out LCMV (*see list box to left) and the rodent viral diseases (not included in this list since they are not transmissible to humans). Euthanasia and necropsy, serology, and microbiology of sick animals with neurologic signs or clinical signs suggestive of inflammation of the brain is essential to diagnose LCMV, rabies, and many of the less common agents.

When one decides to share their life with animals, there is always a risk verses benefit. Each person must decide what that means to them and their family. I can only speak for myself in that the benefit has always been greater than the risk. There are many web sites on zoonotic diseases. All of the following diseases listed in the box on the previous page can be transmitted from rodents to humans. However, if you go to the website and read about the diseases, you will find that most are not a significant issue in pet rodents.

In conclusion, the number of incidents of people becoming ill from LCMV is very low. If you want to find out more, you can visit the Center for Disease Control website: https://www.cdc.gov/healthypets/pets/pocket-pets/lcmv.html.

Editor, Karen Robbins
Q We have a brand new mouse person here that had a prolapsed penis happen to one of her mice and was wondering if there is anything to do for it. Her vets (and I) told her nothing could be done and to put the mouse down. She was giving it fluids and it was eating, urinating, and defecating fine. She is a dog breeder/shower and knew of the problems in dogs and what to do for them so tried on the mouse. She did eventually put him down when nothing she tried worked. Is there anything you can do in a case like this? Does it ever resolve itself?

A In our research breeding colonies, we occasionally see mice with a prolapsed penis. However, for humane reasons, most are euthanized without treatment. If the mouse can urinate, topical antibiotic treatment can be given. However, treatment is not usually successful because there has been substantial damage, and the penis is unable to contract even if the inflammation is resolved. With dogs, treatment is often more successful because it is usually easier to treat and address the problem before there is irreversible damage.

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