Most common poultry diseases The poultry is considered as a common bird, which is brought up in many countries. Also there are large number of ranches that are specialized for poultry bringing up. So that, the medical care of these fowls is a must, to know more about their diseases, and how it occur and spread, and the most important thing is how to control and treat it. In this article, we will discuss some of the common poultry diseases which are listed below: The poultry diseases are divided into four categories based on the origin of the disease: Viral Disease They are diseases caused by action of virus inside the cells of the animal. The most common Viral Disease occurred in poultry: Newcastle disease This veterinary disease happens due to the infection of bird cells with Newcastle virus, which stick to the red blood cells. This virus is transferred to the chickens due to ingestion of contaminated food. The symptoms of this veterinary disease are: hard breathing, coughing, twisting of head and neck (remarkable sign), and lack of appetite. Infectious Bronchitis disease This veterinary disease occurs in chickens because of the a virus action in the airways of the chickens. This virus is similar to Corona virus, and can be controlled by using of sterilizers. The common symptoms are: hard breathing, sneezing, coughing, nasal secretions, and bad egg quality. Smallpox disease This disease is caused by a specific type of virus called: Fowlpox virus. The birds infected with this disease have red and black spots on different parts of their bodies, especially areas near mouth and beek. The disease begins with white small spots, which gradually enlarge in size and change to irritations with red and black colors. Bacterial Diseases These diseases originate from bacterial action inside the animal body. The most common bacterial Disease occurred in poultry: Salmonella bacteria disease This veterinary disease happens to the chickens and ducks, due to effects of some types of bacteria called: Salmonella. This bacteria infects the poultry from ingestion of contaminated food by excrement of other infected chickens. The bacteria goes to the bowel of the chicken, and cause some disturbances in digestive system like: diarrhea and constipation. Fowl cholera Occured in the fowls by effect of some bacteria called: Pastrella Maltusida. This bacteria can infects the fowl either by breathing, or by ingestion food contaminated by this bacteria. The symptoms are: diarrhea with yellow or green excrement, straining, fever, and in the extreme cases the fowl dies. Infectious Cold disease Also called Coryza. This veterinary disease is occured in poultry due to infection of airways with some type of bacteria called: Haemophilus. The infection could happen by several ways: by contact with another infected bird, breathing, eating. This bacteria infects the respiratory system causing: inflammation of airways and nasal sinuses, continuous mucus runny, hard breathing, and coughing. Parasitic Disease The parasitic diseases happen due entering of some worms and insects into the digestion path of the animal. The most common parasitic Disease occurred in poultry: Internal Parasitic roundworms/tapeworms disease These diseases are happened due to ingestion of contaminated food with these harmful worms. The chickens pick up some gravels, that are mixed with eggs of these worms. These eggs hatch and mature inside the bowel of the chicken, causing many problems to it. The symptoms are: stomach disturbances, diarrhea, constipation,straining, and excrement companied by blood and worms External parasitic insects diseases These external parasites infect the chickens and other birds on their outside skins. The contact with an infected animal or eating polluted food are main reasons for this veterinary disease. The symptoms are: appearance of some red and white spots on the skin, disappearing of feathers from some parts of the fowl body,and irritations of the skin. Fungal Diseases This veterinary disease is occurred in poultry because of the effect of some types of fungi that are in contact with the animal. The most common fungal Disease occurred in poultry: Fungal toxins diseases This veterinary disease happens due to ingestion of some feeds contaminated with toxic fungi. These feeds are usually stored under unsuitable conditions, causing these harmful fungi to originate in the feeds. The most common fungi existing in poultry feeds are: Aspergillus. These toxic fungi affects the quality of the feeds. So, the fowl health is affected as well. The symptoms are usually notable at the eggs of the bird, some other symptoms are: general weakness and loss of appetite.