Small ruminant lentiviruses, caprine arthritis encephalitis virus, and Maedi-Visna virus cause diseases that result in significant productive losses, mostly in dairy animals. These viruses belong to the Retroviridae family, Lentivirus genus, and constitute a heterogeneous group, which may generate implications for the diagnosis and control of small ruminant lentiviruses. Losses caused by them are associated with reproductive failure, short productive life, and decreased milk production by the infected animals. In addition, these viruses may reduce milk quality, affecting the production of dairy products such as cheese. Small ruminant lentiviruses lead to indirect losses, decreasing herd value and forcing the development of epidemiological trade barriers for animal germplasm. Control of small ruminant lentiviruses is important to promote optimal milk production and to reduce costs with medicine and technical assistance. This control may vary in caprine and ovine populations of each country, according to seroprevalence, variety of breeds, and peculiarities of the practiced management.

The aim of this study was to evaluate in vitro and in vivo the effect of sodium dodecyl sulfate (SDS) on the caprine lentivirus (CLV) in colostrum and milk. This was performed to develop a practical and efficient method of blocking the lactogenic transmission of the virus. In the in vitro experiment, colostrum and milk were treated with 0.25%; 0.50% and 1% SDS. Then, somatic cells of colostrum and milk were submitted to co-culture with caprine synovial membrane cells (CSM). In the in vivo test, goats were fed with colostrum and milk provided from CLV-positive goats treated with SDS in the same concentrations used in the in vitro experiment. Animals were tested by nested polymerase chain reaction (nPCR) and Western blot (WB) assays. In the in vitro experiment, inhibitory activity against CLV without inactivation occurred in colostrum with all SDS concentrations. However, concentrations of 0.25 and 0.5% SDS presented only inhibitory activity against CLV in milk cells, and 1% concentration provided inactivation of the virus. In the in vivo tests, none of the three concentrations of SDS was effective in inactivating LVC in colostrum or goat milk, which was confirmed by seroconversion and presence of proviral DNA in animals afterwards.

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Background: Caprine Arthritis Encephalitis (CAE) is a disease that causes productive losses in dairy goat flocks due to the reduction in milk production, followed by lesions in joints and mammary glands. An early diagnosis is essential, considering that there is frequent occurrence of asymptomatic animals. Hence, this study aimed to perform a comparison of immunological and molecular based diagnostic tests, represented by Agar Gel Immunodiffusion (AGID), Western Blot (WB) and nested Polymerase Chain Reaction (nPCR). In addition, the mammary glands (MG) of dairy goats were clinically evaluated. Material, Methods & Results: Blood collection and clinical examination were performed in 1191 dairy goats of 12 farms located in Northeastern and Southeastern regions of Brazil. Serological (AGID, WB) and molecular (nPCR) test results were compared and the data, along with MG alterations, were analyzed using Epi-info 7 and WinEpiscope 2.0. Seroprevalence in AGID test was 41.14% (490/1191). In WB, 51.47% (613/1191) of animals were seropositive and nPCR detected 69.44% (827/1191) positive animals. Hence, WB was more sensitive (P < 0.001) than AGID. However, nPCR detected more positive animals than AGID (P < 0.001) and WB (P < 0.001). The analysis of mammary glands revealed that 105 out of 1096 nanny goats presented alterations, of which 101 presented altered consistency, 16 presented elevated temperatures and 60 had enlarged retromammary lymph nodes. There was significant statistic difference (P < 0.05) only when comparing the results of serological tests with MG alterations.Discussion: In general, AGID technique is most frequently used when screening flocks for the disease due to the practicality and low cost this test presents. However, the results demonstrated that AGID detected the lowest number of positive animals. This low sensitivity that the test presented may be attributed to its antigen-antibody interaction mechanism, considering that agar gel precipitation requires multiple interactions. In addition, WB was more effective than AGID in detecting antibodies. On the other hand, nPCR was important for the detection of infected animals that serological tests failed to detect. The intermittence of immunological response observed in the serological tests may be explained by the variation of antibodies levels that may occur during life. Likewise, viral compartmentalization would justify the intermittent detection of proviral DNA. Hence, the results can be influenced by the viral intermittence, test sensitivity, late seroconversion and statistic values that can be calculated (sensitivity, specificity, positive predictive value, negative predictive level and kappa). Crossing the results of the diagnostic tests with the different mammary gland alterations, it was shown that there was a statistically significant difference (P <0.05) only in the comparison of the results of the serological tests with GM alterations. Everything indicates that the humoral or cellular immune system being on stimulus is more propitious to find these changes. In conclusion, WB was more sensitive than AGID and, considering that nPCR can detect a larger number of animals infected with the goat lentivirus, it must be associated with a sensible serological test, such as Western Blot. In addition, infected animals have alterations in MG, which is more frequent in cases with positive serological results.

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This study examined the effectiveness of control measures for caprine arthritis-encephalitis in a herd with 431 dairy goats in an intensive rearing system. All animals older than six months were initially tested by agar gel immunodiffusion (AGID) and separated into seropositive and seronegative. Control measures were implemented for two years and ten months. Five serological examinations were subsequently performed two by AGID and three by the Western Blot (WB) technique. In these tests, animals that tested negative in the previous serological examination were evaluated along with those older than six months which had not yet been examined. The effectiveness of control was evaluated based on the incidence of the disease. Seroconverted animals were stratified according to age, physiological status and dam serology. For the effect of time, logistic regression was performed at the 5% significance level, with values converted into likelihood. General incidence and incidence as a function of age and physiological status were evaluated by analysis of variance, with means compared by Tukey’s test at 5% significance. The ratio test was used for incidence and physiological status, and the agreement between the AGID and WB tests was determined by the Kappa coefficient. Animals that seroconverted and were born to positive dams were compared with those born to dams negative at birth by the Chi-square test, and the same was applied for the number of discarded animals. Initially, 54.24% (179/330) positive and 257 seroconverted animals were identified after the start of control. Higher incidence occurred in the animals aged between 13 and 36 months and in lactating does. Seroconversions among offspring of seropositive dams were higher than in the offspring of seronegative dams (p < 0.001). High infection rates were identified in the sires. The obtained results were not satisfactory, as the measures did not help to prevent new cases, indicating that there are moments of infection yet to be elucidated. On farms that aim to control the disease, the following measures are required in addition to those already recommended: use of diagnostic tests with less frequency; application of high-sensitivity tests in the offspring; immediate separation of kids from dams at birth; separation of kids according to the serological status of the dams; inclusion of kids from unsupervised births in the group of kids from positive dams; and keeping positive and negative animals on different farms or greatly distanced. In herds for which there is an intention to establish control, it is important to determine whether the productive losses associated with the disease are greater than the costs of implementing more efficient measures.

This study aimed to evaluate by means of Nested Polymerase Chain Reaction (nPCR), co-cultivation and sequencing, with genetic comparison between strains (mother/newborn), the occurrence of vertical transmission of Small Ruminant Lentiviruses (SRLV) from naturally occurring nannies infected for their offspring. For the detection of SRLV seropositive progenitors, blood was collected from 42 nannies in the final third of gestation in tubes with and without anticoagulant. The diagnostic tests used were Western Blot (WB) and nPCR. During the period of birth, the same blood collection procedure was performed on 73 newborns at zero hours of birth, with the same diagnostic tests. Seventeen blood samples from seven-day-old kids, proven positive for SRLV by nPCR, chosen at random, were subjected to coculture in goat synovial membrane (GSM) cells for 105 days. The pro-viral DNA extracted from the cell supernatant from the coculture was subjected to nPCR. For DNA sequencing from the nPCR products, nine positive samples were chosen at random, four nannies with their respective offspring, also positive. Each sample was performed in triplicate, thus generating 27 nPCR products of which only 19 were suitable for analysis. Among the 42 pregnant goats, in 50% (21/42) pro-viral DNA was detected by nPCR, while in the WB, only 7.14% (3/42) presented antibodies against SRLV. Regarding neonates, of the 73 kids, 34 (46.57%) were positive for the virus, using the nPCR technique, while in the serological test (WB), three positive animals (4.10%) were observed. The coculture of the 17 samples with a positive result in the nPCR was confirmed in viral isolation by amplification of the SRLV pro-viral DNA. When aligned, the pro-viral DNA sequences (nannies and their respective offspring) presented homology in relation to the standard strain CAEV Co. It was concluded that the transmission of SRLV through intrauterine route was potentially the source of infection in the newborn goats.

Background: Contagious agalactia is an infectious disease caused by Mycoplasma agalactiae (M. agalactiae) that occurs in small ruminants leading to productive and economic losses. Due to the similarity of clinical signs presented in Caprine Arthritis Encepha­litis (CAE), which is a viral disease, a differential diagnosis is important. Therefore, this study aimed to investigate the presence of anti-Mycoplasma agalactiae antibodies in dairy goat flocks in Ceará State and possible correlation with CAE.Materials, Methods & Results: The research was performed in four mesoregions in Ceará State (Metropolitan Region of Fortaleza- MRF; Northeast Ceará - NeC; North Ceará - NC; Sertões in Ceará - SC), from which 16 productions located in 10 cities with the highest representativeness for goat milk production within the State or mesoregion were sampled. A total of 417 females and 69 males (486 animals) of breeds with dairy production aptitude, pure or crossbreed, maintained in semi-intensive or intensive systems, were tested. Blood serum was obtained by venipuncture of the jugular vein with vacuum pressure syringe followed by centrifugation at 1,500 g for 10min. Antibodies against the caprine arthritis encephalitis virus (CAEV) were detected with micro technique of agarose gel immunodiffusion (AGID) and Western Blot (WB). The anti-Mycoplasma agalactiae antibodies were detected with commercial kit of enzymatic immunoassay (IDEXX Laboratories™). Seroprevalence of M. agalactiae in dairy goat flocks in Ceará State was 0.62% (3/486). From the total of 16 visited productions, 18.75% (3/16) had seropositive animals for M. agalactiae located in MRF, NC and SC mesoregions. CAE was diagnosed in 56.25% (9/16) of productions with AGID and in 81.25% (13/16) with WB. In addition, 5.2% (25/486) of animals were seropositive for CAE with AGID and 16.6% (80/486) with WB. Animals that reacted positive for M. agalactiae were all females of pure breed with milk production aptitude in distinct mesoregions submitted to intensive rearing system. None of these animals was positive in neither test (AGID or WB) for CAE. Therefore, no correlation of results obtained in diagnosis of M. agalactiae by ELISA and CAEV by AGID or WB (P < 0.05) was identified. However, two out of three productions that were positive for M. agalactiae presented positive results for CAEV with frequencies of 10% and 20%.Discussion: Seroprevalence of M. agalactiae in Ceará State was low in comparison with other Brazilian states and even other countries. However, the presence of the pathogen in more than one mesoregion indicates that the disease occurs in different loca­tions within the State. Therefore, flocks in Ceará are susceptible to the infection, which may be favored by uncontrolled commerce that occurs with deficient surveillance, associated with the importation of animals to improve flock genetic quality. The presence of the pathogen in dairy goats may contribute to significant losses in the local production. On the other hand, CAE was diagnosed in nearly all productions proving the dissemination of this lentivirus infection among dairy goat flocks in Ceará State. Although an association between these diseases was not identified, the presence of a retrovirus in the organism may favor co-infection with another micro-organism, promoting the deficiency in the immune system of the host. In conclusion, M. agalactiae is present in different mesoregions of the Ceará State and control measures should be adopted in short term to prevent pathogen dissemination and, consequently reduce economic and productive losses in the local dairy goat production. No correlation was identified between the prevalence of infection by CAEV and M. agalactiae in this study.Keywords: correlation, diagnosis, caprine lentivirus, mycoplasmosis.