Health issues in these rats became obvious before we laid hands on them. When we approached places where they hid, we heard rattling sounds of their breath: they were severely affected by cold. The colder became the nights, the worse became their respiratory problems.
As a result, each batch of the rescued rats immediately went to Kyiv and visited a vet out of gate. The vet sterilized females at early stages of pregnancy and prescripted treatment to be received by each rattie at home. Almost all ratties had to take doxycycline because of respiratory problems. Some had tumors removed.
One girl named Motria had a huge belly and we thought her to be heavily pregnant...
...instead, she appeared to have a tumor the size of a peach!
One boy name Dymok ("Little Smoke") had rotten teeth (on the photo below, he is the blue one on the bottom), so the vet left him to herself, because he needed injection therapy. With rats, caries means that the infection has gotten into bones. By now, he has grown healthy teeth, but he still stays with the vet to complete the course of treatment.
With rats, it is important to get treatment from a dedicated rodentologist, because "regular" vets may be unaware of ratty specifics. For example, a vet must provide gas anesthesia for treatment of such small creatures.
The importance of getting treatment from a professional was demonstrated by the following situation. There is no rodentologist in Kryvyi Rih, so we gave advice to local rat owners, mostly on proper rat food, cages and bedding. When the owners complained about rat diseases, we asked them to contact rodentologists, even if those are in other cities. We told them what could be the treatment, but we insisted on visiting a rat vet. One guy complained that his rats coughed, and he didn't get an answer from one of the best rodentologists. So we told him: "With our rats, cough was a symptom of infection that was cured with a certain dose of doxycycline. Some rodentologists are reluctant to consult online, because they are fed up with sly-arsed people trying to cadge free service. You'd better go and see a rodentologist in Kyiv, and then she will consult you online in the future". The guy first was too busy or lazy to go to Kyiv and tried to treat his rats with doxycycline. Well... that helped, because doxycycline removes the symptoms. But then he suddenly became able to send his rats to a vet in Kyiv, and the vet told us that they in fact didn't need that medicine, and the cough was caused by using hay as bedding! That is, unprofessional advice (although that of an experienced rat owner) removed the symptom, but not reason, and was somewhat harmful, because taking unnecessary antibiotics leads to development of tolerance to them.
Anyway, all the rescues ceased to cough and feel much better. Soon, they will be completely healthy. The post-op ratties don't have any complications, too.