About influenza  A(H7N9) virus What is the influenza A(H7N9) virus? Influenza A H7 viruses are a group of influenza viruses that normally spread among birds. The influenza A(H7N9) virus is one smaller group among the larger group of H7 viruses. Although some H7 viruses (H7N2, H7N3 and H7N7) have sometimes been found to infect  humans, no human infections with H7N9 viruses have been reported until recent reports from China. What are the main signs of human infection with influenza A(H7N9) virus? So far, most patients with this infection have had severe pneumonia . Signs include fever, cough and shortness of breath. However, information is still limited about the full area of disease that infection with influenza A(H7N9) virus might cause. How did people become infected with the influenza A(H7N9) virus? Some of the confirmed cases had connections with animals or with an animal environment. The virus has been found in a pigeon in a market in Shanghai. It is not yet known how persons became infected. The possibility of animal-to-human spread is being looked into. Is it safe to eat meat like chicken and pork products? Influenza viruses are not spread through eating well-cooked food. Because influenza viruses are made inactive by normal temperatures used for cooking (so that food reaches 70degC in all parts), it is safe to eat properly prepared and cooked meat. Diseased animals and animals that have died of diseases should not be eaten. In areas experiencing outbreaks, meat products can be safely eaten only if they are properly cooked and properly handled during food preparation. The eating of raw meat and uncooked blood-based dishes is a high-risk practice and should be discouraged. Is it safe to travel to China? The number of confirmed cases in China is very low. WHO does not advise the application of any travel measures with respect to visitors to China, nor to persons leaving China. Are Chinese products safe? There is no evidence to link the present cases with any Chinese products. WHO advises that people should not fear to trade them at this time. According to this passage the way of spreading the influenza A(H7N9) virus is  _  .
animal-to-human transmission person-to-person transmission consuming badly-cooked food not determined yet
Question: About influenza  A(H7N9) virus What is the influenza A(H7N9) virus? Influenza A H7 viruses are a group of influenza viruses that normally spread among birds. The influenza A(H7N9) virus is one smaller group among the larger group of H7 viruses. Although some H7 viruses (H7N2, H7N3 and H7N7) have sometimes been found to infect  humans, no human infections with H7N9 viruses have been reported until recent reports from China. What are the main signs of human infection with influenza A(H7N9) virus? So far, most patients with this infection have had severe pneumonia . Signs include fever, cough and shortness of breath. However, information is still limited about the full area of disease that infection with influenza A(H7N9) virus might cause. How did people become infected with the influenza A(H7N9) virus? Some of the confirmed cases had connections with animals or with an animal environment. The virus has been found in a pigeon in a market in Shanghai. It is not yet known how persons became infected. The possibility of animal-to-human spread is being looked into. Is it safe to eat meat like chicken and pork products? Influenza viruses are not spread through eating well-cooked food. Because influenza viruses are made inactive by normal temperatures used for cooking (so that food reaches 70degC in all parts), it is safe to eat properly prepared and cooked meat. Diseased animals and animals that have died of diseases should not be eaten. In areas experiencing outbreaks, meat products can be safely eaten only if they are properly cooked and properly handled during food preparation. The eating of raw meat and uncooked blood-based dishes is a high-risk practice and should be discouraged. Is it safe to travel to China? The number of confirmed cases in China is very low. WHO does not advise the application of any travel measures with respect to visitors to China, nor to persons leaving China. Are Chinese products safe? There is no evidence to link the present cases with any Chinese products. WHO advises that people should not fear to trade them at this time. According to this passage the way of spreading the influenza A(H7N9) virus is  _  .
A. animal-to-human transmission
B. person-to-person transmission
C. consuming badly-cooked food
D. not determined yet
Answer: