How cats and people become infectedĬats can get infected with B. Kittens are also more likely to scratch and bite while they play and learn how to attack prey. henselae infection and to spread the germ to people. Kittens younger than 1 year are more likely to have B. henselae in their blood, although most cats with this infection show NO signs of illness. Contact your doctor if you develop any symptoms of cat scratch disease or infection.ĬSD is caused by a bacterium called Bartonella henselae. Wash cat bites and scratches well with soap and running water. Later, the person’s lymph nodes near the original scratch or bite can become swollen, tender, or painful. A person with CSD may also have a fever, headache, poor appetite, and exhaustion. The infected area may appear swollen and red with round, raised lesions and can have pus. About three to 14 days after the skin is broken, a mild infection can occur at the site of the scratch or bite. The disease spreads when an infected cat licks a person’s open wound, or bites or scratches a person hard enough to break the surface of the skin. The closure of the ductus arteriosus, ductus venosus, and foramen ovale completes the change of fetal circulation to newborn circulation.An enlarged lymph node in the armpit region of a person with cat scratch disease, and partially healed wounds from a cat scratch on the hand.Ĭat scratch disease (CSD) is a bacterial infection spread by cats. The shift in pressure stimulates the foramen ovale to close. They also lower the pressure in the right atrium. These changes raise the pressure in the left atrium of the heart. An increase in the baby's blood pressure and a major reduction in the pulmonary pressures reduce the need for the ductus arteriosus to shunt blood. As the lungs expand, the alveoli in the lungs are cleared of fluid. With the first breaths of life, the lungs start to expand. Oxygen and nutrients from the mother's blood are released into the fetus' blood.Īt birth, the umbilical cord is clamped and the baby no longer gets oxygen and nutrients from the mother. In the placenta, carbon dioxide and waste products are released into the mother's circulatory system. This blood then enters the umbilical arteries and flows into the placenta. Most of this blood is shunted through the ductus arteriosus to the descending aorta. A small amount of the blood continues on to the lungs. This less oxygenated blood is pumped from the right ventricle into the pulmonary artery. Instead of going back through the foramen ovale, it goes into the right ventricle. Very little of this less oxygenated blood mixes with the oxygenated blood. After circulating there, the blood returns to the right atrium of the heart through the superior vena cava. This is the large artery coming from the heart.įrom the aorta, blood is sent to the heart muscle itself and to the brain and arms. When the blood enters the right atrium, most of it flows through the foramen ovale into the left atrium.īlood then passes into the left ventricle. This is the chamber on the upper right side of the heart. Inside the fetal heartīlood enters the right atrium. Waste products from the fetal blood are transferred back across the placenta to the mother's blood. A small amount of this blood goes straight to the liver to give it the oxygen and nutrients it needs. This is also a shunt that lets highly oxygenated blood bypass the liver to the inferior vena cava and then to the right atrium of the heart. Most of this blood is sent through the ductus venosus. This is a major vein connected to the heart. The blood then reaches the inferior vena cava. The enriched blood flows through the umbilical cord to the liver and splits into 3 branches. Oxygen and nutrients from the mother's blood are sent across the placenta to the fetus. The ductus arteriosus moves blood from the pulmonary artery to the aorta. This shunt moves blood from the right atrium of the heart to the left atrium. The shunt that bypasses the lungs is called the foramen ovale. That's because these organs will not work fully until after birth. The purpose of these shunts is to bypass the lungs and liver. These are small passages that direct blood that needs to be oxygenated. The fetal circulatory system uses 3 shunts.
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