Tortoiseshell is a coat colouration in domestic cats named for its similarity to tortoiseshell pattern.The most common tortoiseshell colouration is black tortoiseshell (black and red). Tortoiseshell can occur in combination with other cat coat patterns, such as tabby and colourpoints.
You can spot the warning signs of feline leukemia virus, also known as FeLV, if you know what to look for. When the disease is detected early enough, you may even be able to take steps to lengthen the life of your cat.

Feline Leukemia Virus (FeLV) is a serious disease that often begins with vague, easy-to-miss symptoms before progressing to more severe health complications. Understanding the feline leukemia symptoms to watch for can be the key to getting your cat the care they need at the earliest possible stage.

4 Initial Symptoms of Leukemia in Cats Two to four weeks after exposure to FeLV, your cat may experience these acute-phase symptoms: Fever Lethargy or weakness Vomiting Swollen lymph nodes 13 Additional Symptoms of Cat Leukemia Feline leukemia may severely compromise any or all of the bodily systems.

Leukemia symptoms vary, depending on the type of leukemia. Common leukemia signs and symptoms include: Fever or chills. Persistent fatigue, weakness.
A tortoiseshell cat, also known as a tortie, is a cat born with a fur pattern resembling the mottled red and black tortoiseshell material. Even the paw pads might have some spotting. Tortoiseshell is usually reserved for multicolored cats that have rather small or no white markings.