Most kittens are very susceptible to infection by roundworms. They are normally contracted by ingesting the eggs, which can come from another cat, the litter box, or even its mother's milk. Vomiting, stomach bloating, and a poor coat are common symptoms, but the one most often noticed is sudden diarrhea.
The most common ailment suffered by pets is an infection by fleas, due in part to how common they are and how easy they are to contract. Cats tend to eat then as they groom themselves, so they can be difficult to diagnose. When dealing with older animals, they are little more than an annoyance, but kittens do not have as much blood as older animals. This means that a serious flea infection can result in a dangerous loss of blood if not treated.
Fading Kitten Syndrome
Fading kitten syndrome is a generic term that applies to all manner of diseases and afflictions. The most noticeable symptoms include: diarrhea, dehydration, and lethargy. Dehydration is particularly serious, and requires immediate medical help. These kittens simply do not get better without medical help.
Conjunctivitis refers to an eye infection that is common to cats of all ages. If it is not treated promptly, it can result in permanent blindness. The eye tends to weep fluid, and is usually kept shut. There may also be a green or yellow discharge present. It is also extremely contagious.
While these are among the most common conditions that new born kittens are known to suffer from, there are countless more. There are, however, a few things that you can watch for that are common to a wide variety of conditions. If your kitten has any sudden change in eating habits, urinary or defecation habits, or exhibits any other sudden change, it is best to play it safe and take it to a veterinarian for a more thorough examination.