Abstract
Background:
Caprine arthritis encephalitis virus (CAEV) is a small ruminant lentivirus that causes chronic ailments in goats and greatly influences herd productivity and health. Though found worldwide, few studies have examined its prevalence in Iran.

Aim:
This study aimed to determine the prevalence of CAEV in goats from western provinces of Iran (Lorestan, Ilam, and Kurdistan) using the highly sensitive nested polymerase chain reaction (PCR) method.

Methods:
A cross-sectional survey took place between March and December 2024 to capture all seasons due to a possible seasonal effect. A multistage random sampling plan was used to select 15 farms distributed among the three provinces. Blood samples were collected from 170 neonatal and 421 adult goats, for a total of 591. DNA isolation, following a slight modification of a published protocol and nested PCR to detect CAEV by targeting the gag gene, took place. Amplification products were detected through agarose gel electrophoresis.

Results:
Out of 591 samples analyzed, 101 (17.08%) were found to be CAEV positive. Prevalences of infection differed among provinces: Kurdistan (27.38%), Lorestan (14.87%), and Ilam (12.13%). Prevalence of herd infection included 7.1%–40%, of which 13 of 15 herds proved to be CAEV positive. No significant associations were found between CAEV infection and age (p = 0.51), between CAEV infection and gender (p = 0.84), nor between CAEV infection and season (p = 0.32), indicating year-round transmission of this virus.

Conclusion:
This study provides the first report on the prevalence of CAEV in three western provinces of Iran. Considering that CAEV is economically challenging and marked by lower production of milk, higher culling rates, and veterinary expenditures, regionalized prevention programs such as regular surveillance and better husbandry standards should be a focus. This work presents the initial thorough prevalence evaluation of CAEV in western Iran through nested PCR and reasserts those comprehensive nationwide epidemiological studies are required. Further studies must aim to characterize CAEV strains that are currently circulating to inform efficient disease control and management measures.

Key words: Caprine arthritis encephalitis virus; Epidemiology; Goat herds; Small ruminant lentivirus; Nested PCR.