Infection Rates ofOrthohalarachne attenuataandOrthohalarachne diminuata(Acari: Halarachnidae) inArctocephalus australis(Zimmermann, 1783) (Pinipedia: Otariidae)

Abstract

ÍNDICEEn el examen externo, el principal hallazgo fue la mala condición corporal (57,1%).En corazón, no se evidenciaron hallazgos macroscópicos ni microscópicos relevantes.En el examen macroscópico de vías aéreas se encontró exudado mucopurulento (40%), edema (31,4%) y cuerpos extraños (leche, agua, piedras) (20%). Además, en pulmones se observó congestión (74,3%), edema (14,2%), exudado mucopurulento (11,4%) y cuerpos extraños (8,6%). En el 48,6% de los animales examinados se encontraron parásitos del género Orthohalarachne, principalmente en tráquea y bronquios. Se presentó neumonía en distintos grados en el 37,1% de los animales.Los principales hallazgos microscópicos en vías aéreas fueron hiperemia (26,9%) y congestión (19,2%) y en pulmones fueron congestión (93,5%), hiperemia (87%), edema intersticial (67,7%) y alveolar (61,3%), infiltrado inflamatorio (45,2%) y enfisema (22,6%).Se concluye que el período más adecuado para realizar estudios post mortem en cachorros de lobo fino austral en la colonia de isla Guafo, es a partir de la segunda semana de enero, por otra parte, los estudios sobre parasitismo por Orthohalarchne deberían ser a partir de la primera semana de febrero. El promedio de los pesos de los cachorros fue 6,1 kg, mientras que el de las longitudes estándar fue de 71,2 cm. El 57,1% de los animales presentó emaciación, lo que puede ser considerado como causa de muerte en algunos casos. Los hallazgos macroscópicos más relevantes en vías aéreas y pulmones fueron los parásitos del género Orthohalarachne, el exudado mucopurulento asociado a neumonía y los cuerpos extraños. Los hallazgos microscópicos más importantes fueron la hiperemia, el edema intersticial y alveolar, el infiltrado inflamatorio y el enfisema alveolar.Palabras claves: Lobo fino austral, Arctocephalus australis, Orthohalarachne, isla Guafo. SUMMARY "CARDIORESPIRATORY FINDINGS IN SOUTH AMERICAN FUR SEAL (Arctocephalus australis, ZIMMERMAN 1783) PUPS, FOUND DEAD IN GUAFO ISLAND, REGION DE LOS LAGOS, CHILE"The aim of the present study was to describe the main cardiorespiratory findings in a post mortem examination of South American fur seal (Arctocephalus australis) pups, found dead, between December of 2004 and March of 2005, of the reproductive colony at Guafo island (43º 36'S y 74º 43'W), Region de los Lagos, Chile.35 necropsies of Arctocephalus australis pups were performed. A tamponed formalin solution 10% was used taking samples of trachea, lungs and heart, as well as a 70% alcohol solution for parasite samples. All this material was later analyzed at the Instituto de Patología Animal at Universidad Austral de Chile.The main finding at the external exam was a bad corporal condition (57.1%).There were no prominent macroscopic nor microscopic finds when examining heart.In the macroscopic examination of the airways the main findings were mucopurulent exudate (40%), edema (31.4%) and foreign bodies (milk, water, stones) (20%). In lungs this study found congestion (74.3%), edema (14.2%), mucopurulent exudate (11.4%) and foreign bodie...

Nasopulmonary mites (Halarachnidae) of coastal Californian pinnipeds: Identity, prevalence, and molecular characterization

“…Cross-contamination during collection can be ruled out since no harbor seals were necropsied on the same day as this elephant seal. Although coinfection with O. attenuata and O. diminuata has been reported in other studies ( Kim et al, 1980 ; Gastal et al, 2016 ), we did not find any O. diminuata among our specimens; this may be attributed to sampling bias for two reasons: first, we only sampled mites from the nasopharynx, and O. diminuata reportedly prefers to parasitize the lungs ( Kim et al, 1980 ; Gastal et al, 2016 ). However, larvae of both species have been found in the nasopharynx ( Fay and Furman, 1982 ), which is logical since transmission is thought to occur via larval expulsion, followed by invasion of the nares of additional hosts ( Kurochkin and Sobolewsky, 1971 ; Fay and Furman, 1982 ).…”

“…No reports of mite prevalence are available for elephant seals or sea lions, but prevalence among a small sample of Galápagos sea lions ( Zalophus wollebaeki ) was 16.7% ( Dailey et al, 2005 ). Although nasopulmonary mites have not previously been reported in Guadalupe fur seals, in South American fur seals ( Arctocephalus australis ) the reported prevalence varies from 9.4% in Peru ( Seguel et al, 2018a ), to 68.2% in Brazil ( Gastal et al, 2016 ), and 100% in Chile ( Seguel et al, 2018b ). Our values likely underestimate the true prevalence of nasopulmonary mite infestation in each host population because examination of the respiratory tract was limited to the nasopharynx in some cases, and because mites may be difficult to detect during necropsy ( Pesapane et al, 2018 ).…”

“…Since they were first described in 1847 ( Allman, 1847 ), halarachnid mites have been documented in more than a dozen marine mammal species worldwide ( Rolbiecki et al, 2018 ), yet few reports include estimates of prevalence ( Kenyon et al, 1965 ; Dunlap et al, 1976 ; Kim et al, 1980 ; Fay and Furman, 1982 ; Baker, 1987 ; Munro et al, 1992 ; Dailey et al, 2005 ; Kuiken et al, 2006 ; Alonso-Farré et al, 2012 ; Gastal et al, 2016 ; Seguel et al, 2018a , 2018b ) and our prior study in southern sea otters ( Pesapane et al, 2018 ) is the only study to estimate nasopulmonary mite prevalence in California marine hosts. Our summary data suggests that nasopulmonary mite infestation is the norm among California sea lions (74.1%), northern fur seals (73.3%), and northern elephant seals (46.6%), while infestation is less common among harbor seals (18.7%) and Guadalupe fur seals (8.8%) ( Table 3 ).…”

First report of a severe nasopulmonary acariasis caused by Orthohalarachne diminuata Doetschman, 1944 (Acari: Halarachnidae) in a captive South American sea lion (Otaria flavescens Shaw, 1800)

“…Referring to this classification system, infestation intensities of H. halichoeri in grey seals ( Halichoerus grypus Fabricius, 1791) stranded along the North Western Spanish Atlantic coast ( Alonso-Farré et al, 2012 ) and of Orthohalarachne spp. in stranded South American fur seals in Brazil ( Gastal et al, 2016 ) were evaluated. As such, former authors reported O. attenuata in 68.2% of examined South American fur seals, while five individuals (22.7%) showed a co-infestation with O. diminuata .…”

“…have been reported, e.g. 48.6–100% in South American fur seals ( Arctocephalus australis Zimmermann, 1783) ( Páez, 2007 ; Gastal et al, 2016 ; Seguel et al, 2018b ), 74.1–85% in California sea lions ( Zalophus californianus Lesson, 1828) ( Kuzmina et al, 2018 ; Pesapane et al, 2021 ), and 73.3–100% in Northern fur seals ( Callorhinus ursinus Linnaeus, 1758) ( Dunlap et al, 1976 ; Kim et al, 1980 ; Kuzmina et al, 2021 ; Pesapane et al, 2021 ). Co-infestations of both Orthohalarachne species are thereby regularly recorded ( Kim et al, 1980 ; Gastal et al, 2016 ).…”