Infectious diseases in dogs can be caused by a variety of bacteria, viruses, parasites, and fungi. The signs and symptoms of an infectious disease in dogs can vary depending on the specific disease and the stage of the infection. Here are some common signs and symptoms to watch out for:

1. Fever – One of the most common signs of an infectious disease in dogs is a fever. A normal temperature range for dogs is between 100.5-102.5 degrees Fahrenheit, so a temperature above this range may indicate an infection.
2. Lethargy – Dogs with infectious diseases may become lethargic and show a lack of energy or enthusiasm for their usual activities. They may also sleep more than usual.
3. Loss of appetite – Dogs with infectious diseases may lose their appetite and refuse to eat or drink. This can lead to dehydration and further health problems.
4. Vomiting and diarrhea – Infectious diseases can cause gastrointestinal symptoms such as vomiting and diarrhea. These symptoms can be accompanied by abdominal pain, bloating, and discomfort.
5. Coughing and sneezing – Respiratory infections, such as kennel cough and canine influenza, can cause coughing, sneezing, and other respiratory symptoms.
6. Skin rash – Some infectious diseases can cause skin rashes or lesions. These may appear as bumps, blisters, or scabs, and can be itchy or painful for the dog.
7. Eye and nose discharge – Infectious diseases can cause discharge from the eyes or nose. This discharge may be watery or thick and may be accompanied by sneezing or coughing.
8. Neurological symptoms – In some cases, infectious diseases can affect the nervous system and cause symptoms such as seizures, confusion, and disorientation.

If you notice any of these signs and symptoms in your dog, it is important to take them to the veterinarian for a thorough examination and diagnosis. Early detection and treatment can help to prevent the infection from becoming more severe and potentially life-threatening.