In general terms, the invention is concerned with the adaptation and propagation of parainfluenza types 1, 2 and 3 in tissue cultures prepared from embryonated hens' eggs, or human diploid lung fibroblasts. More particularly, this invention is directed to the development of live virus vaccines against the parainfluenza group of agents following serial passage in chick embryo tissue culture, or human diploid lung fibroblasts.
Parainfluenza is a respiratory infection that seems very similar to influenza (i.e. flu). However, it is typically less severe than flu. It may cause flu-like symptoms, and needs to be distinguished from other similar conditions, such as the common cold or flu. Exact determination of a diagnosis of parainfluenza is not actually required in order to treat its effects, and as such, it is a diagnosis that is rarely given. Nevertheless, always seek prompt professional in-person medical advice for diagnosis of any flu-like illness.
After natural infection with HPIV, most children and adults develop measurable levels of these antibodies in the serum; these antibodies have been shown to be correlated with disease prevention and amelioration in adults. Local interferon production has been noted in about 30% of children with HPIV infection. Although immunity to HPIV infection is long-lasting, reinfection may occur many times throughout life, at variable intervals, even in the presence of neutralizing antibodies.
The vocal cords of the larynx become grossly swollen, causing obstruction to the inflow of air, which is manifested by inspiratory stridor. In adults, the virus is usually limited to causing inflammation in the upper parts of the respiratory tract. In infants and young children, the bronchi, bronchioles and lungs are occasionally involved, which may reflect on the small size of the airways and the relative immunological immaturity. Viraemia is neither an essential nor a common phase of infection.
Infections are most common in fall and winter. Parainfluenza infections are most severe in infants and become less severe with age. By school age, most children have been exposed to parainfluenza virus. Most adults have antibodies against parainfluenza although they can get repeat infections.
It is a group of viruses that usually cause severe cold-like symptoms, including fever and chills and less commonly, pneumonias. It is spread directly by contact with saliva and indirectly by contact with droplets when a person coughs or sneezes. It is also spread indirectly by hands, tissues, eating utensils and other articles freshly contaminated with respiratory secretions of an infected person.
Human parainfluenza viruses (HPIVs) are a group of four distinct serotypes of single-stranded RNA viruses belonging to the paramyxovirus family. They are the second most common cause of lower respiratory tract infection in younger children. Repeated infection throughout the life of the host is not uncommon. Symptoms of later breakouts include upper respiratory tract illness as in a cold and sore throat. The incubation period of all four serotypes is 1 to 7 days.
There are four types of Parainfluenza virus, all of which can cause upper respiratory infections or lower respiratory infections (pneumonia) in adults and children. The virus is responsible for approximately 40-50% of croup cases and 10-15% of bronchiolitis and bronchitis cases and some pneumonias. The exact number of cases of parainfluenza is unknown but suspected to be very high.
