Pneumostrongylus Tenuis Research Articles

THE INCIDENCE, DEVELOPMENT, AND EXPERIMENTAL TRANSMISSION OF PNEUMOSTRONGYLUS TENUIS DOUGHERTY (METASTRONGYLOIDEA: PROTOSTRONGYLIDAE) OF THE MENINGES OF THE WHITE-TAILED DEER (ODOCOILEUS VIRGINIANUS BOREALIS) IN ONTARIO

Pneumostrongylus tenuis was found throughout the year in the cranium of 41% of 172 adult deer examined in Algonquin Park. Incidence was higher in summer (46%) than winter (24%). Two fawns were infected (October and March). Worms also occurred on the spinal dura mater and in veins of the dura. Thus, incidence of infection was higher than indicated by examinations of craniums. Larvae developed in species of Discus, Zonitoides, Deroceras, Triodopsis, Stenotrema, and Lymnea sp. Four fawns were infected experimentally. Fourth- and fifth-stage larvae were found in the brain and spinal cord of one fawn examined at 25 days. Fifth stages were found in the tissue and between the meninges of the spinal cord of a fawn examined at 40 days. Subadults were found on the spinal and cerebral dura mater of a fawn autopsied at 50 days. The final fawn passed larvae 91 days after exposure. At 115 days after exposure, mature worms were found on or in the cerebral dura; two were found in the intercavernous sinus. The inflamed dura was covered by haemorrhagic, fibrous exudate containing larvae and developing eggs. Eggs and larvae were found in vessels in the pia-arachnoid and near veins in the dura. Lungs contained minute nodules with one to three eggs. Undeveloped eggs, reaching the lungs via the blood, formed embolisms that fibrosed. In regions of the lungs with numerous developing eggs and larvae there was congestion, inflammation, haemorrhage, and fibrosis of interstitial tissue.

The nematode lungworms (suborder Strongylina) of North American deer of the genus Odocoileus

1. Seven species of lungworms are so far known to occur in North American deer of the genus Odocoileus: Dictyocaulus filaria (Rudolphi, 1809) Railliet & Henry, 1907; D. viviparus (Bloch, 1782) Railliet & Henry, 1907; Varestrongylus alpenae (Dikmans, 1935) n.comb.; Pneumostrongylus tenuis n.sp.; Elaphostrongylus odocoilei Hobmaier & Hobmaier, 1934; Protostrongylus coburni Dikmans, 1935; and P. macrotis Dikmans, 1931. Specimens (from deer) of all these species except Dictyocaulus filaria and Protostrongylus coburni have been studied in the course of this work.2. Two subspecies of Odocoileus virginianus (Boddaert) and two of O. hemionus (Rafinesque) have been reported as hosts for lungworms. These may be listed with their established lungworm parasites as follows:Common white-tailed or Virginia deer, Odocoileus v. virginianus (Boddaert): Dictyocaulus viviparus, Varestrongylus alpenae—new record, Pneumostrongylus tenuis—new record.Northern white-tailed deer, Odocoileus v. borealis Miller: Dictyocaulus filaria, D. viviparus, Varestrongylus alpenae, Protostrongylus coburni.Rocky Mountain mule deer, Odocoileus h. hemionus (Rafinesque): Dictyocaulus viviparus, Protostrongylus macrotis.Columbian black-tailed deer, Odocoileus h. columbianus (Richardson): Dictyocaulus filaria, D viviparus—new record, Elaphostrongylus odocoilei.3. A new species, Pneumostrongylus tenuis, is based on a single male lungworm from a bronchiole of Odocoileus v. virginianus. Pneumostrongylus tenuis differs from P. calcaratus Mönnig, 1932, genotype of Pneumostrongylus Mönnig, 1932, in spicular, gubernacular, and bursal characters.4. Pneumostrongylus alpenae Dikmans, 1935, is transferred to the genus Varestrongylus Bhalerao, 1932, as a result of the study of specimens of Pneumostrongylus alpenae and Varestrongylus pneumonicus Bhalerao, 1932, genotype of Varestrongylus. The former becomes Varestrongylus alpenae (Dikmans, 1935) n.comb. Also placed in this genus are Varestrongylus sagittatus (Mueller, 1890) n.comb. (syn. Strongylus, or Protostrongylus sagittatus) and Varestrongylus capreoli (Stroh & Schmid, 1938) n.comb. (syn. Protostrongylus capreoli).5. The reports of Protostrongylus coburni from Odocoileus v. virginianus by Goble (1943) were based on larvae and adult lungworms in sections of lung tissue. Subsequent observations by Cheatum (in litt.) strongly indicate that these were actually Varestrongylus alpenae.6. The structure of the gubernaculum in Protostrongylus macrotis is redescribed, and the conclusion reached that this form may be regarded as an aberrant species of Protostrongylus. Appendages at the distal ends of the gubernacular crura are given the name pedes (sing, pes), and the sclerotized are, found in the bursa of a number of genera of the Protostrongylinae, the name arcus.7. The fact that crura have not been described for the gubernaculum of Elaphostrongylus cervi Cameron, 1931, genotype of Elaphostrongylus Cameron, 1931, whereas E. odocoilei Hobmaier & Hobmaier, 1934, possesses them must be regarded as a possibly significant difference between the two species; but it is suggested that E. cervi may be found to have these structures. Therefore E. odocoilei is left in Elaphostrongylus.