Thursday, May 28, 2015

Treating a Colony

When the Animal Care team began observing skin lesions on some of the naked mole rats recently, they called Dr. Maas from ZooVet to diagnose the problem. At first, a handful of animals had fairly obvious skin problems; everything from isolated bumps to reddened areas and swelling. The infections were mostly aesthetic and, from what we observed, were not causing any serious health problems. After careful observation, we found that 41 of our total 61 colony members had at least some sign of the infection. Dr. Maas assessed the situation and set up a treatment plan.

Naked mole rat colonies function as a team. Workers gather and share food, sleep in piles to conserve heat and pool moisture, split up tasks, from cleaning and guarding tunnels to breeding and bearing young. All this communal behavior means that when one colony member has a problem, it will probably impact the whole group.
Dr. Maas suspected that an ongoing decision to lower cage temperatures had made the animals susceptible to skin lesions. If we raised temperatures we could halt its spread but we would still have to treat all the animals showing current symptoms.

Unfortunately there are a great many unknowns about how mole rats interact with medicines. One known is that their guts contain complex groups of beneficial microbes. We wanted an antibiotic that would not harm these vital helpers. Injectable medication bypasses the gut. Giving a shot is also – perhaps surprisingly – less invasive to the animals than squirting medicine into their mouths. We tested our medication of choice, Ceftazidime, on four animals and observed them closely for a few days to make sure there were no serious side effects. When we detected no problems, we began a treatment program for all 41 impacted animals.

Forty-one animals, each given two injections a day for ten days means a lot of shots and a lot of animal sorting. To save sorting time, we marked the mole rats to be treated with a colored marker. Physically separating the medicating group for ten days might risk a battle when they are reintroduced.

So twice a day, the affected animals are pulled out, weighed, and given a medication dose based on their current weight. A full belly can mean several grams difference so they are weighed at every treatment. This treatment will continue for a total of 10 days.

Most of the mole rats are pretty unperturbed by the whole process, with the exception of the ones who take the guard role in the colony. The procedure seriously annoys them.

Midway through the treatment plan, there are no observable problems from the medication and fewer and fewer skin lesions among the animals. Staff is getting better at administering treatments. Of course, everyone is looking forward to the end of this process and having a healthier colony. Especially the naked mole rats.

1 comment:

  1. Sorry to hear that PSC's mole rat colony has been affected by the epidemic desbribed, but kudos to the author(s) of this blog for having described the situation in considerable depth while in language that a layperson such as myself can readily understand. I hope that your efforts to restore the colony to acceptable health is comprehensive and speedy.