Swine brucellosis in Indonesia

Summary

Brucella suis biotype 1 was isolated from 13.1% of the pigs slaughtered in Kapuk Jakarta, West Java and from 15.09% of the pigs slaughtered in Surabaya, East Java. The prevalence of B. suis by means of the Rose Bengal Plate Test, was 22.3% for West Java and 14.9% for East Java. The Rose Bengal Plate Test detected more B. suis infected animals (73% of the infected animals) than did the Complement Fixation Test (41%) and the Serum Agglutination Test (54.5%).

The high infection rate is a potential health danger for the abattoir workers.     

Human brucellosis: seroprevalence and risk factors related to high risk occupational groups in Tanga Municipality, Tanzania

The objective of this study was to describe the prevalence of brucellosis in various occupations in Tanga, Tanzania. During the year 2004, serum samples were collected from volunteers in various occupations and screened for brucella antibodies using Rose Bengal Plate Agglutination Test. Information on occupation, kind of work and contacts with livestock was collected and age and sex were recorded. The overall sero prevalence of antibodies to Brucella abortus was 5.52%. One variable in a multivariate regression model was significantly associated with seropositivity to B. abortus: abattoir workers. The prevalence of antibody was significantly higher (P < 0.05) among personnel employed in high-risk jobs such as cutting animal throats and cleaning slaughtered animals parts. None of the other factors investigated was associated with seropositivity to B. abortus. This study documents the serological evidence of B. abortus infection for the first time in abattoir workers in Tanzania.     

An evaluation of three serological tests for antibody to Brucella suis in pigs

The Rose Bengal Plate Agglutination test (RBT), the complement fixation text (CFT) and the tube agglutination test (TAT) were applied to serums from 345 feral and 80 domestic pigs sampled at slaughter. At least 2 of the 3 serological tests were applied to each serum. Tissues from all pigs were cultured for Brucella suis and the degree of culture effort was categorised from 1 to 4 in decreasing order. Fifty-eight feral and 35 domestic pigs were culture-positive. A greater proportion of culture-positive pigs was obtained for category 1 and 2 culture effort. Tissues yielding B. suis most often were mandibular, gastrohepatic and external iliac lymph nodes, spleen and various abdominal organs. Infection in domestic pigs was associated with exposure to feral pigs. The sensitivity (Se) in culture-positive pigs of the RBT (79.1%) was significantly greater than that of either the CFT (49.1%) or TAT (51.1%). The specificities (Sp) in culture-negative pigs were 81.2% for the RBT, 90.8% for the CFT and 81.0% for the TAT. A more realistic estimate of Sp for the RBT was considered to be 97.6%, based on serological results from 31,326 domestic pigs routinely tested for regulatory purposes. The RBT was clearly superior to the other 2 tests in this study. However, a more sensitive screening test would be preferable for use in a test and slaughter eradication program. The RBT would be a suitable confirmatory test.     

Serological response of cattle after vaccination and challenge with Brucella abortus

New and currently used serological procedures were evaluated using sera from cattle that were challenged with B. abortus S544 (S544) after vaccination with either B. abortus S19 (S19) or B. abortus 45/20 (S45/20) as calves or adults. In animals vaccinated with S19, titres to the indirect haemolysis test (IHLT) rose more slowly, declined more rapidly and involved fewer animals than did titres to the complement fixation test (CFT). In animals vaccinated with S45/20 the rough antigen complement fixation test (RCFT) showed persistent titres. At slaughter the IHLT and CFT were found to be more specific and more sensitive than the Rose Bengal Plate Test (RBPT) and Serum Agglutination Test (SAT) in the detection of cattle infected with B. abortus.     

Le depistage systematique de la brucellose humanine par le test au Rose Bengale en milieu agricole d'apres une etude dans le centre-ouest de la France sur 89 000 exploitants et salaries

A previous comparative study of 806 human serums showing the similarities and differences between Wright agglutination test, Renoux hem agglutination test and Rose Bengal Plate Test confirmed the practical interest of the easy and cheap Rose Bengal Plate Test in detecting human brucellosis.IRSA of Tours made with this test a systematic detecting of human brucellosis concerning 89 000 persons of agricultural occupation from the middle-west district of France.It revealed a brucellosis infection much more important than we expected among the adult agricultural population: about 2.5% and even 5 or 10% with some populations. The attention of doctors must be called to the so far unsuspected frequency of brucellisation among agricultural people.     

Serologic Prevalence of Brucellosis in Horse Stables in Two Northern States of Nigeria

Despite the endemicity of brucellosis in Nigeria, reports on equine brucellosis are rare. The Rose Bengal Plate Test (RBPT) was used to determine the serologic prevalence of Brucella abortus antibodies amongst 75 horses from three stables in two States of northern Nigeria. The highest prevalence (22.7%) was recorded in stable C located in Plateau State and the lowest (6.7%) was found in stable B in Kaduna State. The overall prevalence determined was 14.7%. There is need for the inclusion of horses in brucellosis surveillance and control strategies in Nigeria to safeguard people at high risk.     

Prevalence of Streptococcus suis types 1 and 2 in domestic pigs in Australia and New Zealand

Using an indirect fluorescent antibody test, 54 per cent of 734 palatine tonsils of conventional pigs slaughtered in Australia and New Zealand were found to be infected with Streptococcus suis type 1 and 73 per cent of 959 were infected with S suis type 2. Variations in the prevalence of infection in pigs from different herds were thought to be due to differences in the sample sizes rather than to real differences in the prevalence between herds. The prevalence of infection with S suis was similar in pigs of either sex and in different age groups. Streptococcus suis type 2 was detected in the blood of 3 per cent of apparently normal pigs slaughtered at a meat processing plant. The presence of this organism in edible tissue may pose a health risk to consumers and meat-workers. Both S suis types 1 and 2 were detected in the vaginas and uteri of slaughtered pigs and the female reproductive tract could be another site for the carriage of infection. Piglets from sows with vaginas infected with S suis type 2 became infected earlier than piglets from sows with uninfected vaginas. No infected male reproductive tracts were detected and venereal transmission of S suis therefore appears unlikely. Three specific pathogen free herds were found to be free from infection with both S suis types 1 and 2. It is concluded that hysterectomy derived piglets are delivered free from infection, whereas some piglets born to sows with uterine and vaginal infections are either born infected or become infected at, or soon after, birth.     

Assessment of performance of selected serological tests for diagnosing brucellosis in pigs

Swine brucellosis due to Brucella suis is considered an emerging zoonotic disease whose control is based on serological testing and the subsequent culling of seropositive animals or the full depopulation of affected flocks. Here we assessed the performance of several serological tests (Rose Bengal Test [RBT], indirect ELISA [i-ELISA], blocking ELISA [b-ELISA], and two competitive ELISAs [c-ELISA]) for diagnosing swine brucellosis caused by B. suis biovar 2. Both frequentistic and Bayesian statistical inference were used. A frequentistic analysis, using sera from known gold standard (GS) populations (i.e., from truly infected or brucellosis free animals), resulted in maximum (100%) diagnostic sensitivity (Se) and specificity (Sp) in the RBT, i-ELISA and b-ELISA tests. However, c-ELISAs resulted in lower diagnostic Se (ranging from 68.5% to 92.6%, according to the different cut-offs selected). A Bayesian analysis of tests yielding the best diagnostic performance with GS sera (RBT, i-ELISA and b-ELISA), but using a large collection of field sera, resulted in similar Se among tests but markedly lower (≈ 80%) than that resulting from the frequentistic analysis using the GS serum populations. By contrast, the estimated Sp in the Bayesian analysis was only slightly lower than 100%, thus similar to that obtained frequentistically. Our results show that adequate diagnostic tests for brucellosis in swine are available, but also emphasize the need for more extensive validation studies before applying these tests under field conditions.     

The Streptococcus suis Epidemiological Analysis of Healthy and Infected Swine in Guangdong Province

To investigate the epidemics of Streptococcus suis in Guangdong province, 228 samples from infected pigs,and 698 samples from healthy pigs including 243 samples from tonsils of slaughtered pigs and 455 nasal swabs of healthy pigs were analyzed.The results showed that the positive rate of Streptococcus suis of infected,healthy and slaughtered pigs were 82.02%(187/228),42.20%(192/455) and 32.10%(78/243),respectively.187 strains of Streptococcus suis were isolated from infected pigs and serotyped in 11 serotypes,including serotype SS1,SS2,SS3,SS4,SS7,SS8,SS9,SS16,SS19,SS29 and SS31, in which serotype SS2(16.58%),SS3(9.63%) and SS19 (7.49%) were dominant,flowed by SS7(6.95%)and SS9(5.34%),and 48.66% strains were non-typabled.Meanwhile,154 strains of Streptococcus suis from healthy swine(including farms and slaughter houses) were classified into 17 serotypes,including serotype SS2,SS3,SS4,SS5,SS7,SS8,SS9,SS10,SS12,SS15,SS16,SS17,SS19,SS21,SS23,SS29 and SS30,in which SS2(18.83%) and SS29(14.94%)were dominant,flowed by SS16(6.50%) and 31.82% strains were non-typabled.     

广东地区健康猪群和发病猪群猪链球菌流行病学调查分析

为了解广东地区猪群中猪链球菌（Streptococcus suis,SS）的流行情况,本研究对在广东地区养殖场采集的228份发病猪群样品及698份健康猪群样品（包括455份鼻拭子样品及243份屠宰场扁桃体样品）进行了SS携带情况的统计分析。结果显示,发病猪群SS的阳性率为82.02%（187/228）,健康猪群的SS阳性率为42.20%（192/455）,其中屠宰场屠宰猪群的SS阳性率为32.10%（78/243）。将从发病猪群分离到的187株SS及健康猪群（含养猪场和屠宰场）分离得到的154株SS进行血清型定型分析,结果显示,发病猪群共检测到11个血清型,包括SS1、SS2、SS3、SS4、SS7、SS8、SS9、SS16、SS19、SS29和SS31型,主要以SS2、SS3和SS19型为主,分别占16.58%、9.63%和7.49%;其次为SS7型（6.95%）和SS9型（5.34%）,未定型菌株占48.66%;健康猪群共检测到17个血清型,包括SS2、SS3、SS4、SS5、SS7、SS8、SS9、SS10、SS12、SS15、SS16、SS17、SS19、SS21、SS23、SS29和SS30型,主要以血清型SS2和SS29型为主,分别占18.83%和14.94%,其次为SS16型（6.50%）,未定型菌株占31.82%。     

Validation of fluorescence polarization assay (FPA) and comparison with other tests used for diagnosis of B. melitensis infection in sheep

Fluorescence polarization assay (FPA) is a new test for the serological diagnosis of Brucella spp. infection in animals. The FPA is validated for the diagnosis of B. melitensis infection in sheep. For this purpose, 166 sera originated from natural infected sheep (verified by culture) and 851 sera originated from healthy animals (reared in areas where B. melitensis was never been isolated) were tested. The optimum cut-off value that offers the highest diagnostic sensitivity (DSn) and diagnostic specificity (DSp) was determined at 87mP with the use of ROC analysis. The DSn and DSp of FPA using this cut-off value are calculated at 97.6 and 98.9% with a 95% confidence interval (CI) of 93.9-99.3% and 98.0-99.5%, respectively. The DSn and DSp of FPA have been assessed also using as positive reference (n=587), sera that gave positive results at least in two tests used for diagnosis of B. melitensis in sheep as Rose Bengal Test (RBT), modified Rose Bengal Test (m-RBT), complement fixation test (CFT), indirect Elisa (i-Elisa) and competition Elisa (c-Elisa) originated from animals reared in flocks infected by B. melitensis. The optimum cut-off value using the above panel of positive reference sera was the same offering a DSn of 95.9% with a 95% CI, 94.0-97.4%, since the DSp remains the same. The DSn and DSp as well as performance, accuracy and agreement of FPA's result were compared with those of other tests used. The accuracy of FPA is very high, similar with that of i-Elisa. FPA is a promising assay, which offers a DSn and accuracy better that of those of the tests currently approved for the diagnosis of B. melitensis in sheep and goats. Due to its simplicity, the sort time that results can be obtained and its accuracy it can be used and improve the laboratory testing capacity as well as the efficacy of the eradication program based on test-and-slaughter policy.     

荣昌县生猪肠道寄生虫感染情况调查

目的摸清重庆市荣昌县生猪的肠道寄生虫感染情况,从而为有效防控猪的肠道寄生虫感染提供依据。方法荣昌是我国著名地方猪“荣昌猪”的故乡,我国养猪大县之一,作者于2007年4月至2007年11月,在该县20个镇选择具有代表性的规模化猪场、散养户和屠宰场,对种公猪、母猪、仔猪及肥育猪肠道寄生虫感染情况和屠宰场宰杀的肥猪肠道寄生虫虫体感染情况进行了调查。共检查了832份集约化饲养猪的粪便、l133份农户散养猪的粪便,并检查了200头屠宰肥猪的肠道。结果13．1％的集约化饲养猪感染猪蛔虫,5．4％感染猪鞭虫．14．6％感染食道口线虫,14．8％感染球虫（包括艾关尔球虫及等孢球虫）,3．6％感染结肠小袋纤毛虫。对散养猪．这些数值分别是6．7％,4．8％,23．2％,13．8％,及4．9％。4％的宰杀肥猪检出猪蛔虫,3．5％检出猪鞭虫,52．0％感染食道口线虫。混合感染很常见。结论本项调查表明,荣昌生猪的寄生虫感染较为严重,应引起有关方面的足够重视。应尽快开展猪肠道寄生虫感染的综合防控工作,以保障养猪业的健康快速发展。     

Prevalence of brucellosis and infectious bovine rhinotracheitis in organized dairy farms in India

This study was carried out to investigate the prevalence of bovine brucellosis and infectious bovine rhinotracheitis (IBR) in organized dairy farms with history of abortion in India. ELISA and Rose Bengal Plate Test (RBPT) were used to detect the seropositive animals and the test results indicated that 22.18% and 13.78% animals were declared as sero-positive by ELISA and RBPT, respectively. Milk Ring Test (MRT) was carried out only in one farm and 12.82% of the tested animals were turned positive. Culture examination analysis of milk samples, two animals revealed the presence of organisms indistinguishable from Brucella spp. The organism was confirmed as brucella by morphological characteristics and biochemical tests. An overall sero-prevalence of antibodies against IBR was found to be 60.84%. None of the genital and nasal swab samples was found to be positive for presence of bovine herpesvirus -1 (BHV-1) on repeated passage in Madin-Darby Bovine Kidney (MDBK) cell lines. Brucella and IBR considered as the causal agent for abortions in these farms. The present study indicates the urgent need and the necessity for control of these infectious diseases which cause heavy economic losses to the organized farms.     

Use of Mass Vaccination with a Reduced Dose of REV 1 Vaccine for Brucella melitensis Control in a Population of Small Ruminants

Mass vaccination with reduced dose 1/50 Rev 1 strain live vaccine (1–2 109 colony forming units), administered subcutaneously, over a four and a half year period reduced the prevalence of Brucella melitensis in Kuwait's small ruminant population from 5.8% in 1993 to 2.02% in 1997.Serological test results using the Rose Bengal Plate Test, Rivanol Agglutination Test and Complement Fixation showed no evidence of persistence of positive serology in animals nine or more months after vaccination. Questionnaires and post-vaccination flock inspections found that the effects on gestation (abortions) were minimal – and not proven to be due to the vaccine.The conclusion from these findings is that mass vaccination with reduced dose Rev 1 administered by the subcutaneous route is a practical field strategy for control of Brucella melitensis.     

Experimental airborne transmission of Streptococcus suis capsular type 2 in pigs.

Experimental airborne transmission of Streptococcus suis type 2 was studied in specific pathogen free piglets. Forty piglets were allotted to five groups of eight 7-week-old animals and housed in three separated units. Negative control pigs (group 1) were housed in unit A and infected batches were housed in units B (group 2) and C (groups 4). In units B and C, non-inoculated groups (groups 3 and 5, respectively), 40 cm distant from the respective inoculated group and without any physical contact between them, also took place. Six animals of groups 2 and 4 were inoculated intravenously with 2 x 10(8) colony forming units (cfu) of a mild and a high virulent S. suis strains, respectively. The remaining animals in these groups and pigs from groups 1, 3, 5 received broth medium in the same way. Differences among virulence of S. suis capsular type 2 were observed in inoculated pigs of groups 2 and 4. Pigs from group 2 became carriers, showing only mild symptoms. By contrast, animals from group 4 presented an acute form of the disease. All the indirect contact pigs in groups 3 and 5 had S. suis in palatine tonsils from day 6 after the infection and they presented clinical manifestations similar to those observed in experimentally infected pigs. Two direct contact animals were also contaminated in the upper respiratory tract but surprisingly they did not show any symptoms. Airborne transmission of S. suis in experimentally pigs was demonstrated in the present study. Indirect infections, as described in this study, are a more realistic way to infect pigs than other experimental procedures and may be used to further study the pathogenesis of the infection caused by this important pathogen.     

A study of cattle infected with Brucella abortus and which showed aberrant serological reactions

SUMMARY Sixty cows, 48 of which had been vaccinated with live Brucella abortus strain 19 (S19) or with killed B. abortus strain 45/20 (S45/20) and 12 of which were unvaccinated animals, were challenged with B. abortus strain 544. Ten of the 27 cattle found to be infected after challenge showed aberrant serological reactions to the Rose Bengal Plate test, serum agglutination test and/or complement fixation test. These 10 cattle were all previously vaccinated with S19 or S45/20. It was concluded that infection in cattle vaccinated with S19 or S45/20 may be more difficult to detect than infection in animals that have no history of vaccination.     

Development of a diagnostic PCR assay based on novel DNA sequences for the detection of Mycoplasma suis (Eperythrozoon suis) in porcine blood

An efficient method of control of porcine eperythrozoonosis (PE) caused by Mycoplasma suis is eradication of infection by detection and removal of infected carrier animals. At present, only a few tests are available for the diagnosis of these latent M. suis infections in pigs. The objective of this study was to develop a PCR assay based on novel DNA sequences for the identification of M. suis-infected pigs. A 1.8 kb EcoRI DNA fragment of the M. suis genome was isolated from the blood of pigs experimentally infected with M. suis. Specificity of the DNA fragment was confirmed by DNA sequence analysis and PCR using primers directed against sequences contained in the 1.8 kb fragment. PCR products of 782 bp in size were amplified only from M. suis particles prepared from the blood of experimentally infected pigs but not from any controls, comprising blood from gnotobiotic piglets and a panel of bacteria including other porcine mycoplasmas. PCR results were confirmed by dot blot hybridisation. The applicability of the PCR assay to diagnose M. suis infections in pigs was evaluated by investigating blood samples from 10 symptomatic pigs with clinical signs typical of porcine eperythrozoonosis and blood samples from 10 healthy pigs. The M. suis-specific PCR product was amplified from all samples taken at episodes of acute disease as well as from samples taken during the latent stage of infection, thus demonstrating the suitability of the PCR assay for detecting latent infected carrier animals.     

Pathogenicity of Eperythrozoon suis alone and when mixed with Babesia trautmanni in experimentally-infected pigs

The pathogenicity of a single infection with Eperythrozoon suis and of a mixed infection of E. suis and Babesia trautmanni in experimentally-infected pigs, was described. In the pigs with a single infection, parasitaemia of E. suis was observed 4 days after blood inoculation. Although parasitaemia with this parasite was also observed on the 4th day in a mixed infection, the parasitaemia of B. trautmanni was not noted until 14 days after inoculation at a period when that of E. suis had started to fall. No parasitaemia was observed in any of the pigs in the splenectomized and unsplenectomized uninoculated control animals. The pigs carrying either single or mixed infections had pyrexia and their temperatures were consistently higher than those of the control animals. Infected pigs also showed anaemia with significant decline in Pcv, Hb and RBC values. The total WBC count rose in the infected pigs and the rise was more pronounced in pigs carrying E. suis alone. In addition, it was only in pigs infected by E. suis alone that a decline in the percentage of neutrophils and a rise in percentage lymphocytes was observed.     

An experimentally induced Chlamydia suis infection in pigs results in severe lung function disorders and pulmonary inflammation

This study was aimed at evaluating the pathophysiology of pulmonary dysfunctions and inflammatory consequences of an acute respiratory chlamydial infection induced experimentally in conventionally raised pigs (aged 39-44 days). Eight animals were exposed to Chlamydia suis (C. suis) and four non-infected animals served as controls. The total observation period was from seven days before challenge to seven days post exposure. While non-infected control pigs did not exhibit any clinical symptoms, animals exposed to C. suis developed fever and were severely respiratory distressed within the first week after exposure. After C. suis infection, pulmonary dysfunctions were characterised by a significant decrease in the diffusion capacity of the lung (i.e. transfer factor of the lung for carbon monoxide; TL CO), a significant increase in the functional residual capacity (FRC), and significant changes in the pattern of ventilation (respiratory rate increased while the tidal volume decreased). In exhaled breath condensate (EBC), leukotriene B(4) (LTB(4)) and interleukin 6 (IL-6) showed a tendency to increase after infection. In the broncho-alveolar lavage fluid (BALF) of C. suis infected pigs, the activity of matrix metalloprotease 9 (MMP-9) was found to be increased compared to controls. BALF cytology was characterised by increased numbers of granulocytes and activated lymphocytes. Pulmonary inflammation in infected pigs was confirmed by post mortem histology. A prominent dissemination of chlamydial bodies in the lung was accompanied by an influx of macrophages, granulocytes and activated T-cells. Data obtained in this study provide new insight into the pathogenesis of acute respiratory chlamydial infections in pigs.     

Parasites in cross-bred pigs in the Upper East region of Ghana

A cross-sectional study was carried out in the Upper East Region (UER) of Ghana in order to estimate the prevalence of parasitic infections in local cross-bred pigs. Out of 60 villages with a human population of 200-1000 inhabitants, 10 villages were randomly selected for the study. The number of pigs varied from 50 to 200 pigs per village. In total 259 faecal samples from growers were collected and examined. Ninety-one percent of the animals excreted parasite eggs. Among these the prevalence of Eimeria spp. was 77.2%, Isospora suis (27%) and Balantidium coli (19.3%).The following helminth eggs were identified: Metastrongylus salmi (19.3%); Physocephalus sexalatus (17.4%); Oesophagostomum spp./Hyostrongylus rubidus (60.6%); Trichuris suis (4.6%); Ascaris suum (12.7%); Ascarops strongylina (8.1%); Brachylaemus suis (1.9%); Paragonimus suis (0.8%); Globocephalus urosubulatus (2.7%); and Schistosoma suis (0.4%). Furthermore, six growers were selected from each village for clinical and postmortem examinations, i.e. 60 in total. The clinical examinations revealed ectoparasites on 98.3% of the animals. The ectoparasites were: Haematopinus suis (66.7%); Boophilus spp. (58.3%); Amblyomma spp (45.0%); Sarcoptes suis (38.3%); and Rhipicephalus spp. (8.3%). All pigs were examined for the presence of haemoparasites. It was found that 23.3% of the animals had haemoparasites. These were: Babesia perroncitoi (23.3%); Babesia trautmanni (13.3%); and Eperytrozoon suis (1.7%). Based on postmortem examinations the following adult worms were identified: Metastrongylus salmi (83.3%); Oesophagostomum dentatum (63.3%); Oesophagostomum quadrispinulatum (38.3%); Hyostrongylus rubidus (23.3%); Ascarops strongylina (76.7%); Globocephalus urosubulatus (20.0%); Strongyloides spp. (1.7%); and Physocephalus sexalatus (65.0%). Cysts of the human tapeworm Taenia solium, Cysticercus cellulosae, were present in 11.7% of the animals. Small pieces of the diaphragm were examined for the presence of Sarcocystis spp.. The prevalence was 28.3%, but no larvae of Trichinella spp. were found. Furthermore, four of the animals (6.7%) had Taenia hydatigena cysts.