The Paramyxoviridae family (Table 1) includes many pathogenic viruses. Many of these viruses are identified more often in young children, including measles, mumps, parainfluenza viruses, and respiratory syncytial virus (RSV). Recently, human metapneumovirus and Nipah virus (Nipah is the area in Malaysia where the virus first was isolated) have been recognized as disease-causing paramyxoviruses. Paramyxoviruses do not have a segmented genome, as do the orthomyxoviruses, and therefore do not undergo antigenic shift. Paramyxoviruses are spherical, enveloped RNA viruses, and all members of this group can cause respiratory disease.

Table1. Paramyxoviruses

Human parainfluenza viruses are important pathogens in children. Viral infection may present as either croup or other upper respiratory diseases in children and adults. The paramyxoviruses are second only to RSV in causing bronchiolitis and pneumonia in infants and young children. The parainfluenza virus has four sub types; parainfluenza 1 is the most common cause of croup, and parainfluenza 3 is second in prevalence to RSV as a disease of infants and very young children. Most children have had an infection with parainfluenza 3 by 2 years of age. Parainfluenza 3 is most often associated with severe disease and fatalities. Not much is known about parainfluenza 4, which is difficult to grow in cell culture. Serologic studies have shown the virus to be as prevalent as parainfluenza 2.

Parainfluenza viral infection is acquired through inoculation of mucous membranes of the respiratory tract with infectious secretions transmitted on fomites or as large, droplet aerosols. Parainfluenza virus can live up to 10 hours on varying surfaces. Laboratory identification is accomplished through the use of cell culture, using primary or continuous cell lines, followed by confirmatory testing using IFA or other methods of antigen detection. Recently, a multiplex molecular diagnostic test that can differentiate the three major types of parainfluenza was approved for clinical use in the United States.

RSV causes bronchiolitis in young children and is the most significant cause of acute lower respiratory tract infection in children under 5 years of age worldwide. Each year in the United States, RSV is responsible for more than 100 deaths and approximately 60,000 to 100,000 hospitalizations. The virus contains a surface protein called F (fusion) protein. F protein mediates host cell fusion into syncytial cells, which are a hallmark of RSV infection and so named because of the CPE syncytia formation in monolayer cell culture. RSV immune serum prevents severe RSV bronchiolitis during the early months of life in susceptible newborns at risk for RSV disease and those with underlying medical conditions, especially in premature children with underdeveloped lungs. Diagnostic testing for RSV also is performed using cell culture and direct antigen detection. Amplified nucleic acid detection is becoming more readily available and desirable because of its increased sensitivity and specificity and faster turnaround time.

Mumps is an acute, self-limiting disease characterized by parotitis (inflamed salivary gland) accompanied by a high temperature (fever) and fatigue. The mumps virus is transmitted through droplets and contact with infected saliva. The measles virus causes an acute, generalized infection often accompanied by a characteristic rash. The hallmark rash of measles infection is referred to as Koplik’s spots, which are bluish white spots with a red halo located on the buccal or labial mucosa. These spots are found on the inner lip or opposite the lower molars in the mouth. The virus is transmitted from person to person through aerosols and infects the mucosal cells of the respiratory tract.

Measles is one of six classic childhood diseases capable of causing a rash or skin eruption (exanthem). The other diseases that cause an exanthem are scarlet fever (which is caused by a bacterium, Group A Streptococcus); rubella (German measles), referred to as atypical scarlet fever; erythema infectiosum (or fifth disease, caused by parvo virus B-19); and roseola (caused by HHV-6).

Since the introduction of the live attenuated child hood trivalent vaccine against measles, mumps, and rubella (MMR), cases of mumps have dropped by more than 99% and measles infections are rare in the United States and Europe. However, these viruses continue to circulate and remain a common illness in developing countries. Mortality rates from measles infections can be as high as 20% as a result of contributing factors such as poor hygiene and malnutrition. These viruses are often brought into the United States by travelers or people from other countries. The potential for an outbreak arises when infected individuals come in contact with unvaccinated individuals, and prompt laboratory investigation of suspect cases is required. Diagnostic testing for these viruses involves serologic analysis of patient serum for IgM and IgG antibodies and cell culture for virus detection and, recently, nucleic acid detection. For measles cell culture, the specimens of choice are respiratory or throat specimens; for mumps cell culture, buccal swabs collected from the inside of the cheek are recommended. These viruses are also shed in the urine; therefore, urine specimens can be examined for their presence.

Metapneumovirus is a newly discovered virus closely related to RSV. It has caused disease presumably throughout human history but has avoided detection in clinical specimens because it is difficult to grow in cell culture. In infections in children, this virus appears to be less common than RSV but more common than parainfluenza virus, making it an important, medically relevant infectious agent. The virus causes bronchiolitis and pneumonia in infants and most likely lower respiratory tract disease in older adults. In infants 6 to 12 months of age, infection with metapneumovirus is likely to show more lower airway involvement. The virus is considered the second or third most common cause of hospitalization for lower airway disease in pediatric patients. Like RSV, metapneumovirus is associated with winter epidemics that vary in severity from year to year. As stated previously, isolation of metapneumovirus from cell culture is difficult, because the virus is very slow to grow and often takes longer than 2 weeks to develop detectable CPE. Nucleic acid testing for viral RNA is becoming more widely available because of the reduced detection time and improved sensitivity of the assays.

Nipah virus is a recently discovered paramyxovirus capable of causing respiratory disease in pigs and acute, febrile encephalitis in humans. The first human out break was identified in 1999. The outbreak was a result of direct contact and viral transmission from diseased pigs and accounted for 265 human cases of viral infection and 108 deaths. Multiple outbreaks have been described in subsequent years. The reservoir for Nipah virus is presumed to be fruit bats, and pigs and other animals are intermediate hosts.

اخر الاخبار

اخبار العتبة العباسية المقدسة

قسم شؤون المعارف يطلق دورة (صفات الشيعة) لعدد من ملاكات العتبة العباسية المقدسة

الهيأة العليا لإحياء التراث تبحث تعزيز التعاون المشترك مع مركز الإمام الباقر (عليه السلام) في إيران

جامعة الكفيل تكرِّم طلبتها المتميزين من ذوي الاحتياجات الخاصة

فريق طبي في مستشفى الكفيل يجري عملية ناجحة لطفل يعاني من تشوّه ولاديّ بالنخاع الشوكي

المزيد

الآخبار الصحية

خصوصا مع تقدم السن.. 6 سلوكيات يومية قد تدمّر صحتك

فاكهة خضراء.. علاج طبيعي فعّال للإمساك واضطرابات الهضم

روسيا تبدأ أولى التجارب السريرية للقاح واعد ضد السرطان

كنز غذائي على طبقك.. ماذا تفعل السبانخ بجسمك؟

المزيد

الآخبار التكنلوجية

رصد نوع نادر من القطط في تايلاند للمرة الأولى منذ عقود

روسيا تخطط لإقامة محطة نووية في القمر خلال العقد المقبل

كيف قاد إيلون ماسك حملة "غروك" لاختراق عرش الذكاء الاصطناعي

ألتمان: الذكاء الاصطناعي سيتجاوز البشر في 2026 !

المزيد

مواضيع ذات صلة

Polyomaviruses

Picornaviruses

Parvoviruses

Properties of Paramyxoviruses

Influenza Virus Replication

Antigenic Drift and Antigenic Shift

Structure and Function of Neuraminidase

Complications of COVID-19

Clinical Features of SARS-CoV-2 and COVID-19

Modes of Transmission SARS-CoV-2 and COVID-19

Papillomaviruses

Arenaviruses