A recent distemper virus outbreak in the growing canine populations of Galapagos Islands: a persistent threat for the endangered Galapagos Sea Lion

Abstract

Canine Distemper Virus (CDV) is a highly contagious virus that can cross mammalian species barriers and has widespread impacts on both domestic animals and wildlife populations. This study describes a recent outbreak of CDV in the Galapagos Islands in 2019. A total number of 125 dogs with clinical signs compatible with CDV were included in this study. Nasal swabs were taken and analyzed by RT-qPCR for the detection of CDV, resulting in a positivity rate of 74.4% (IC95%, 66–81%). Among the CDV positive dogs, 82.2% presented with respiratory signs, 48.8% neurological signs, and 28.9% gastrointestinal signs. CDV has been previously reported in the domestic canine population of the Galapagos Islands in 2001 and 2004. The current study shows how CDV is still a threat for the endemic and endangered Galapagos sea lion, despite recent policies for dog population control and CDV vaccination.

Study of Canine Distemper Virus Presence in Catalonia’s Wild Carnivores through H Gene Amplification and Sequencing

“…CD is an endemic disease, and numerous outbreaks have been documented across various regions globally [31]. In 2023, CD outbreaks were found in Galapagos Islands threatening the endangered Galapagos Sea Lion [32], in captive tigers in Thailand [33], and in Palm civets in India [34]. Recently, CDV was also detected in wild carnivores in multiple European countries, such as Italy, Hungary, Spain, Croatia, and Germany [35][36][37][38][39][40].…”

Seroconversion in Galapagos Sea Lions (Zalophus wollebaeki) Confirms the Presence of Canine Distemper Virus in Rookeries of San Cristóbal Island

“…The last assessment reported that the human/dog ratio was 4.04:1, representing an increase of 55% in the dog population on Santa Cruz Island from 2014 to 2018 [8,10]. This growing canine population can increase the risk of transmission of infectious diseases, such as that caused by the canine distemper virus (CDV), which could severely affect endangered species such as the GSL [11,12]. In turn, parasitic diseases such as heartworm (Dirofilaria immitis) disease and bacterial infections caused by Leptospira spp.…”

“…However, multiple reports of CDV circulation in dogs in the Galapagos Islands were published, indicating that the serological prevalence increased from 22% in 2004 [23] to 36% in 2014 [10], with well-documented outbreaks of CDV killing more than 600 dogs on Santa Cruz and Isabela islands in the early 2000s [10,23]. Recently, a study conducted on Santa Cruz Island reported a total of 125 dogs with clinical signs compatible with CDV infection, with 74.4% (IC95%, 66-81%) of the animals found positive by RT-qPCR for CDV detection [12]. This motivated vaccination campaigns for domestic dogs in the archipelago [12]; however, virus spread at dog-wildlife interfaces is generally not controlled [24].…”

“…Recently, a study conducted on Santa Cruz Island reported a total of 125 dogs with clinical signs compatible with CDV infection, with 74.4% (IC95%, 66-81%) of the animals found positive by RT-qPCR for CDV detection [12]. This motivated vaccination campaigns for domestic dogs in the archipelago [12]; however, virus spread at dog-wildlife interfaces is generally not controlled [24]. Hence, the recent vaccination policies would not prevent CDV infections, which remain a threat for the endangered GSL [12].…”

“…This motivated vaccination campaigns for domestic dogs in the archipelago [12]; however, virus spread at dog-wildlife interfaces is generally not controlled [24]. Hence, the recent vaccination policies would not prevent CDV infections, which remain a threat for the endangered GSL [12].…”