Infection of marmosets with parainfluenza virus types 1 and 3

Simultaneous outbreaks of respiratory disease in wild chimpanzees caused by distinct viruses of human origin

Respiratory viruses of human origin infect wild apes across Africa, sometimes lethally. Here we report simultaneous outbreaks of two distinct human respiratory viruses, human metapneumovirus (MPV; Pneumoviridae: Metapneumovirus) and human respirovirus 3 (HRV3; Paramyxoviridae; Respirovirus, formerly known as parainfluenza virus 3), in two chimpanzee (Pan troglodytes schweinfurthii) communities in the same forest in Uganda in December 2016 and January 2017. The viruses were absent before the outbreaks, but each was present in ill chimpanzees from one community during the outbreak period. Clinical signs and gross pathologic changes in affected chimpanzees closely mirrored symptoms and pathology commonly observed in humans for each virus. Epidemiologic modelling showed that MPV and HRV3 were similarly transmissible (R₀ of 1.27 and 1.48, respectively), but MPV caused 12.2% mortality mainly in infants and older chimpanzees, whereas HRV3 caused no direct mortality. These results are consistent with the higher virulence of MPV than HRV3 in humans, although both MPV and HRV3 cause a significant global disease burden. Both viruses clustered phylogenetically within groups of known human variants, with MPV closely related to a lethal 2009 variant from mountain gorillas (Gorilla beringei beringei), suggesting two independent and simultaneous reverse zoonotic origins, either directly from humans or via intermediary hosts. These findings expand our knowledge of human origin viruses threatening wild chimpanzees and suggest that such viruses might be differentiated by their comparative epidemiological dynamics and pathogenicity in wild apes. Our results also caution against assuming common causation in coincident outbreaks.

Parainfluenza viruses

Human parainfluenza viruses (HPIV) were first discovered in the late 1950s. Over the last decade, considerable knowledge about their molecular structure and function has been accumulated. This has led to significant changes in both the nomenclature and taxonomic relationships of these viruses. HPIV is genetically and antigenically divided into types 1 to 4. Further major subtypes of HPIV-4 (A and B) and subgroups/genotypes of HPIV-1 and HPIV-3 have been described. HPIV-1 to HPIV-3 are major causes of lower respiratory infections in infants, young children, the immunocompromised, the chronically ill, and the elderly. Each subtype can cause somewhat unique clinical diseases in different hosts. HPIV are enveloped and of medium size (150 to 250 nm), and their RNA genome is in the negative sense. These viruses belong to the Paramyxoviridae family, one of the largest and most rapidly growing groups of viruses causing significant human and veterinary disease. HPIV are closely related to recently discovered megamyxoviruses (Hendra and Nipah viruses) and metapneumovirus.

Common Diseases

Many pathogens have been reported to cause disease in the laboratory rat. This chapter concentrates on the pathology of the more common pathogens of the laboratory rat. Based on serologic surveys, parvo viruses are some of the most common viral pathogens in wild and laboratory rat. In general, there are three main serogroups, including Rat virus (RV), H-1 virus, and Ratparvovirus (RPV). Both RPV and RV are tropic for many of the same tissues and they both may result in a persistent infection. However, RPV is antigenically and genetically distinct from RV, and it apparently does not cause clinical signs or lesions in infant rats. M. pulmonis causes natural disease in rats and mice. The infection in young rats is usually clinically silent. In older rats, there are nonspecific clinical signs such as snuffling, chromodacryorrhea, and face and ear rubbing. Several bacteria of the genus Streptococcus can cause clinical disease in rats. All of the streptococci of concern in rats are Gram-positive cocci, and are catalase-negative, nonfermentative, and generally nonmotile. Cilia-associated respiratory bacillus has been identified in rats. In rats, infection is usually asymptomatic although nonspecific clinical signs, such as weight loss and dyspnea, may be observed.

Tumors of the respiratory tract observed at the German Primate Center, 1978-1994

Eight spontaneous pulmonary tumors (four bronchiolar tubular adenomas, two bronchiolar adenocarcinomas, two squamous-cell carcinomas) occurred in a total of 54 adult tree shrews (Tupaia belangeri) of the GPC colonies between 1978 and 1994. The adenomas and adenocarcinomas consisted of tubularly or trabecularly arranged cuboidal to cylindrical cells interspersed with some PAS-positive goblet cells, thus resembling the epithelial lining of respiratory bronchioles of tree shrews. The two squamous-cell carcinomas probably originated from the pulmonary alveoles. Three more pulmonary tumors (one small-cell carcinoma, one bronchial adenoma, one squamous-cell carcinoma) developed in 409 adult callitrichids of the GPC colonies during the same period, and one more bronchial adenoma was observed in a common marmoset (Callithrix jacchus) of another colony located in Göttingen. With regard to the adenomas and squamous-cell carcinomas, a similar cellular origin with the three shrews is assumed. The small-cell carcinoma possibly developed from the bronchial epithelium, provided a pathogenesis parallel to that of human small-cell carcinoma is suggested. Four of the tree shrew pulmonary adenomas/adenocarcinomas and the small-cell Ca were macroscopically visible as yellowish-grey nodules of 1 mm x 1 mm to 15 mm x 15 mm diameter, predominantly involving the main lobes (2 x right main lobes, 2 x left main lobes, 1 x all lobes). The pulmonary tumors of the other animals were below macroscopical detectability.