Evaluation of the sensitivity of the classical swine fever surveillance system in two free zones in Colombia

Abstract

Infection with the classical swine fever virus (CSFV) causes a disease in pigs that ranges from a hyperacute form in which animals die in a few hours to subclinical disease. Due to this wide range of virulence, several complementary surveillance strategies should be implemented for the early detection of the disease. The objective of the present study was to determine the sensitivity of the surveillance system to detect CSFV outbreaks in a free zone (Zone 1) and in a zone undergoing an eradication process (Zone 2) in Colombia. Stochastic scenario tree models were used to describe the population and surveillance structures and to determine the probability of CSFV detection. The total sensitivity of the surveillance system in the case of a single infected farm in Zone 1 was 31.4% (CI 95%: 7.2–54.1) and in the case of 5 infected farms was 85.2% (CI 95%: 67.3–93.7), while in Zone 2 the sensitivities were 27.8% (CI 95%: 6.4–55.1) and 82.5% (CI 95%: 65–92.9), respectively. The on‐farm passive surveillance shows the highest sensitivity for detection of a single CSFV infected farm in both zones (22.8% in Zone 1 and 22.5% in Zone 2). The probability of detection was higher in a family / backyard premise than on a commercial farm in both zones. The passive surveillance at slaughterhouse had a sensitivity of 5.3% and 4.5% for the detection of a single infected farm in Zone 1 and 2, respectively. Active surveillance presented a range of sensitivity between 2.2% and 4.5%. In conclusion, the sensitivity of the surveillance in the two studied zones was quite high, one of reasons for this good sensitivity being the sentinel network based on the voluntary participation of 5,500 collaborators that were trained for the identification and notification of diseases of national interest.

Molecular and Pathological Characterization of Classical Swine Fever Virus Genotype 2 Strains Responsible for the 2013–2018 Outbreak in Colombia

“…In 2000, Colombia initiated a National Program for the Eradication of CSF based on the extensive vaccination, monitoring, and elimination of infected herds [52]. The program drastically reduced the CSF outbreaks, and the 17 departments in Colombia have been classified into three zones: the WOAH-recognized CSF free zone (central-west and the central-east regions), the self-declared CSF free zone (south-east region), and the CSF control zone in the north [53,54]. Despite continuous mass vaccination in the CSF control zone, two major CSF outbreaks have been reported within the past two decades.…”

The impact of using the added value from the point of view of freight forwarders and the Inland Freight Station to operate the Egyptian dry ports

“…The third type is the most widespread in the world, as it combines the characteristics and features of commercial-free zones and industrial zones, that is, it includes both industrial zones and commercial-free zones, also called export processing zones, where the state provides all the requirements necessary for commercial, industrial and service companies to practice their activities, whether It was related to the handling of services, storage, transportation, provision of specialized means and equipment, trained manpower, and other infrastructure services necessary for projects, such as matters related to economic activity (Pineda, 2021).…”

Transboundary Animal Diseases, an Overview of 17 Diseases with Potential for Global Spread and Serious Consequences

“…Diagnosis is made by clinical signs, gross pathology, indirect (serological), and direct (virus isolation, antigen, and nucleic acid) detection of the virus [188][189][190][191][192]. Diagnosis should be made using methods and protocols which are validated according to OIE standards [193], and surveillance is imperative in maintaining a CSF-free zone [188,194]. Inactivation protocols have been described to prevent accidental transmission of the virus by diagnostic samples [195].…”

“…As with African swine fever, following strict biosecurity practices is imperative. Control of movement, adequate surveillance, and prophylactic and emergency vaccination are potentially useful in successful eradication and control programs [194,[226][227][228][229]. Also, as in African swine fever, additional consideration must be given to the presence of infected wild boar [230][231][232][233][234][235].…”