Listeria monocytogenes in ready to eat meat products from Zambia: phenotypical and genomic characterization of isolates

The contamination of ready to eat foods (RTE) products due to Listeria monocytogenes could compromise the products safety becoming a great risk for the consumers. The high presence of L. monocytogenes in RTE products has been described worldwide, but few data are available about these products from African countries. The aims of this study were to report the presence of L. monocytogenes in Zambian RTE products, providing genomic characterization and data on similarity with African circulating strains using whole genome sequencing (WGS). A total of 304 RTE products, produced by different Zambian manufacturers, were purchased at retail, from major supermarkets located in Lusaka, Zambia, comprising 130 dairy and 174 meat products. L. monocytogenes was detected only in 18 (10.3%) RTE meat products of the 174 samples tested. The MLST analysis grouped the 18 L. monocytogenes isolates in 7 clonal complexes (CCs): CC1 (n = 5), CC2 (n = 4), CC9 (n = 4), CC5 (n = 2), CC121 (n = 1), CC155 (n = 1), and CC3 (n = 1). According to the cgMLST results, several clusters were detected, in particular belonging to hyper-virulent clones CC1 and CC2. Regarding the virulence factors, a complete L. monocytogenes Pathogenicity Island 3 (LIPI-3) was present both in the CC1 and CC3, in addition to LIPI-1. Several resistance genes and mobile genetic elements were detected, including Stress Islands, the bcrABC cassette and Tn6188_qac transposon, plasmids and intact prophages. Despite being a first preliminary work with a limited number of samples and isolates, this study helped to increase existing knowledge on contaminated RTE products in Zambia, confirming the presence of hyper-virulent L. monocytogenes CCs, which could play an important role in human diseases, posing a public health concern for consumers.

Identification of Mycoplasma mycoides subspecies mycoides from slaughtered cattle in two transboundary states of North‑eastern Nigeria

This study aimed to perform molecular typing of Mycoplasma mycoides subsp. mycoides from slaughtered cattle in Adamawa and Taraba States, north‑eastern Nigeria. A total of four hundred and eighty (480) samples of lung tissues, nasal swabs, ear swabs and pleural fluids were collected from cattle at slaughter and processed according to standard laboratory protocols. Identification and confirmation were achieved with specific PCR and PCR‑RFLP. An overall M. mycoides subsp. mycoides isolation rate of 6.87% (33/480) was obtained. In Adamawa State, 12 (10.91%) isolates of M. mycoides subsp. mycoides came from both, lung tissues and pleural fluids. While in Taraba State, 5 (7.14%) and 4 (5.71%) isolates of M. mycoides subsp. mycoides came from lung tissues and pleural fluids, respectively. The samples from nasal and ear swabs from the study states were negative for M. mycoides subsp. mycoides. Thirty‑three out of the 37 culture positive isolates were confirmed to be Mycoplasma mycoides subspecies mycoides with the production of a band equivalent to 574‑bp. Molecular typing with restriction endonuclease Vsp1 results in the two bands of 180‑bp and 380‑bp. In conclusion, the study has established an isolation rate of 6.87% for M. mycoides subsp. mycoides. Measures to strengthen movement control in order to minimise the spread of this dreaded disease of cattle were recommended.

Genetic Diversity of Rift Valley Fever Strains Circulating in Namibia in 2010 and 2011

Outbreaks of Rift Valley fever (RVF) occurred in Namibia in 2010 and 2011. Complete genome characterization was obtained from virus isolates collected during disease outbreaks in southern Namibia in 2010 and from wildlife in Etosha National Park in 2011, close to the area where RVF outbreaks occurred in domestic livestock. The virus strains were sequenced using Sanger sequencing (Namibia_2010) or next generation sequencing (Namibia_2011). A sequence-independent, single-primer amplification (SISPA) protocol was used in combination with the Illumina Next 500 sequencer. Phylogenetic analysis of the sequences of the small (S), medium (M), and large (L) genome segments of RVF virus (RVFV) provided evidence that two distinct RVFV strains circulated in the country. The strain collected in Namibia in 2010 is genetically similar to RVFV strains circulating in South Africa in 2009 and 2010, confirming that the outbreaks reported in the southern part of Namibia in 2010 were caused by possible dissemination of the infection from South Africa. Isolates collected in 2011 were close to RVFV isolates from 2010 collected in humans in Sudan and which belong to the large lineage containing RVFV strains that caused an outbreak in 2006–2008 in eastern Africa. This investigation showed that the RVFV strains circulating in Namibia in 2010 and 2011 were from two different introductions and that RVFV has the ability to move across regions. This supports the need for risk-based surveillance and monitoring.

Contagious Bovine Pleuropneumonia: A Comprehensive Overview

Contagious bovine pleuropneumonia (CBPP) is a respiratory disease of cattle that is listed as notifiable by the World Organization for Animal Health. It is endemic in sub-Saharan Africa and causes important productivity losses due to the high mortality and morbidity rates. CBPP is caused by Mycoplasma mycoides subsp. mycoides (Mmm) and is characterized by severe fibrinous bronchopneumonia and pleural effusion during the acute to subacute stages and by pulmonary sequestra in chronic cases. Additional lesions can be detected in the kidneys and in the carpal and tarsal joints of calves. Mmm infection occurs through the inhalation of infected aerosol droplets. After the colonization of bronchioles and alveoli, Mmm invades blood and lymphatic vessels and causes vasculitis. Moreover, Mmm can be occasionally demonstrated in blood and in a variety of other tissues. In the lung, Mmm antigen is commonly detected on bronchiolar and alveolar epithelial cells, in lung phagocytic cells, within the wall of blood and lymphatic vessels, inside necrotic areas, and within tertiary lymphoid follicles. Mmm antigen can also be present in the cytoplasm of macrophages within lymph node sinuses, in the germinal center of lymphoid follicles, in glomerular endothelial cells, and in renal tubules. A complete pathological examination is of great value for a rapid presumptive diagnosis, but laboratory investigations are mandatory for definitive diagnosis. The purpose of this review is to describe the main features of CBPP including the causative agent, history, geographic distribution, epidemiology, clinical course, diagnosis, and control. A special focus is placed on gross and microscopic lesions in order to familiarize veterinarians with the pathology and pathogenesis of CBPP.

Pro-Inflammatory Response of Bovine Polymorphonuclear Cells Induced by Mycoplasma mycoides subsp. mycoides

Mycoplasma mycoides subsp. mycoides (Mmm) is the etiological agent of contagious bovine pleuropneumonia (CBPP), one of the major diseases affecting cattle in sub-Saharan Africa. Some evidences suggest that the immune system of the host (cattle) plays an important role in the pathogenic mechanism of CBPP, but the factors involved in the process remain largely unknown. The present study aimed to investigate the cell response of bovine polymorphonuclear neutrophils (PMNs) after Mmm in vitro exposure using one step RT-qPCR and Western blotting. Data obtained indicate that gene and protein expression levels of some pro-inflammatory factors already change upon 30 min of PMNs exposure to Mmm. Of note, mRNA expression level in Mmm exposed PMNs increased in a time-dependent manner and for all time points investigated; targets expression was also detected by Western blotting in Mmm exposed PMNs only. These data demonstrate that when bovine PMN cells are triggered by Mmm, they undergo molecular changes, upregulating mRNA and protein expression of specific pro-inflammatory factors. These results provide additional information on host-pathogen interaction during CBPP infection.

Prevalence of netB-positive Clostridium perfringens in Italian poultry flocks by environmental sampling

Clostridium perfringens type G is one of the pathogens involved in enteric diseases in poultry. NetB, a pore-forming toxin, is considered the main virulence factor responsible for necrotic enteritis during C. perfringens infection. We carried out a field study involving 14 farms to evaluate the occurrence of netB-positive C. perfringens and the impact of infection in Italian poultry flocks. Environmental samples (n = 117) and 50 carcasses were screened by microbiologic and molecular methods. Microbiologic investigations yielded 82 C. perfringens isolates. DNA was extracted from all samples and screened for α-toxin and NetB encoding genes by real-time PCR. The C. perfringens α-toxin gene was detected in 151 of 167 extracts (90.4%), and 31 of 151 (20.5%) were netB gene positive also. Sixteen isolates from a turkey flock with mild enteric disorders were also netB positive, demonstrating their occurrence not only in broiler but also in turkey flocks. A pulsed-field gel electrophoresis protocol was optimized to evaluate the diversity among isolates and revealed high genetic heterogeneity. The complete NetB toxin-coding gene of 2 C. perfringens isolates from turkey and broiler flocks were analyzed and showed very high relatedness with analogous sequences worldwide.

Brucellosis and chlamydiosis seroprevalence in goats at livestock-wildlife interface areas of Zimbabwe

In Zimbabwe, there have been no chlamydiosis and limited brucellosis studies in goats. This study was conducted to determine the seroprevalence and risk factors of the two diseases in goats at three different livestock-wildlife interface areas: porous, non-porous and non-interface in the south-eastern lowveld of Zimbabwe. Collected sera (n = 563) were tested for Brucella antibodies using the Rose Bengal plate test (RBPT) and the complement fixation test (CFT); and for Chlamydia abortus antibodies using the CFT. All tested goats were negative for Brucella antibodies. Overall, chlamydial seroprevalence was 22%. The porous [c2 = 9.6, odds ratio (OR) = 2.6, p = 0.002] and non-porous (c2 = 37.5, OR = 5.8, p < 0.00001) interfaces were approximately three and six times more likely to be chlamydial seropositive than the non-interface area, respectively. Chlamydial seroprevalence was not associated with sex (c2 = 0.5, OR = 1.2, p = 0.5), abortion history in female goats (c2 = 0.7, OR = 1.3, p = 0.4), keeping goats with cattle (c2 = 0.2, OR = 1.5, p = 0.7) or flock size (c2 = 0.03, OR = 1.4, p = 0.9). Our study provides the first serological evidence of chlamydiosis in goats in Zimbabwe and the results suggest that proximity to wildlife is associated with increased chlamydial seropositivity. Further studies are required to determine the role of chlamydial infection on goat reproductive failure and that of wildlife on C. abortus transmission to domestic ruminants.

"SILAB for Africa": An Innovative Information System Supporting the Veterinary African Laboratories

Introduction: To support African veterinary laboratory services, the Istituto Zooprofilattico Sperimentale dell'Abruzzo e del Molise puts in place an operational system called "SILAB for Africa" (SILABFA); this is a web application used by a laboratory information management system to support laboratory diagnostic activities and to meet the needs of various African countries. SILABFA was designed to collect and manage all necessary information on samples, tests, and test results. Methods: The system involves the entry of sample data on arrival, the tracking of samples through the various sections of the laboratory, and the collection of test results. It automates the generation of test reports and monitors outbreaks through data interrogation functions and eliminates multiple registrations of the same data on paper records. SILABFA is currently installed in Namibia, Botswana, Zambia, Zimbabwe, Tanzania, Uganda, Kenya, Ethiopia, and Cameroon, and installation in Senegal and Ivory Coast is planned for the next few months. After some years of SILABFA usage, it was natural to want to utilize more and more data collected in a homogeneous and consistent way for epidemiological purposes and to cover informative debts toward ministries and other organizations. Conclusion: To improve the availability of good, detailed, and reliable data, as the epidemiological information, SILABFA has been linked to the local animal identification, registration, and traceability system and other relevant national information systems.

Virulence gene profiles of rabbit enteropathogenic Escherichia coli strains isolated in Northern Italy

The virulence gene profile of 26 rabbit enteropathogenic Escherichia coli strains, isolated from 17 colibacillosis outbreaks located in two regions of Northern Italy, was determined using an Echerichia coli virulence DNA microarray. All strains were classified according to their determined biotype, sero- and phylo-group. The distribution of virulence genes encoding for the Locus of enterocyte effacement (LEE), LEE type III secretion system (T3SS), non-LEE T3SS translocated proteins and adherence factors was also determined. All strains but one belonged to phylogroups A and B1. A prevalent association between the O103 serogroup with the rhamnose-negative phenotype (biotype 12 or 14) was found. The most prevalent LEE profile found in tested strains was ler/cesT/espA-1/espB-3/tir-1/eae(beta)/espD-2/escN/eprJ. All strains possessed either the adhesive factor rabbit-2 (afr/2) or the plasmid Rabbit adherence locus (ral) gene and 24 of them an additional individual or combined set of colonization factors efa1/lifA, lpfA and paa genes. Finally, the combined or single presence of a set of LEE and/or non-LEE effector proteins encoding genes, namely espG, cif, map and nle family genes, attested to the genetic potential of investigated strains to induce pathologic lesions to the host. The application of microarray-based technologies in assessing the genetic profile of rabbit E. coli is a reliable, cost-effective candidate for large scale investigations in monitoring programs aimed to survey the circulation of pathogenic strains within rabbit production units, their zoonotic genetic potential and to select E. coli strains eligible for vaccinal prophylaxis in fattening rabbit production.

Sero-prevalence of chlamydiosis in cattle and selected wildlife species at a wildlife/livestock interface area of Zimbabwe

A study was conducted to investigate the seroprevalence and associated risk factors of Chlamydia abortus infection in cattle and some selected wildlife species at selected interface areas at the periphery of the Great Limpopo Transfrontier Conservation Area in Zimbabwe. Three study sites were selected based on the type of livestock-wildlife interface, porous livestock-wildlife interface (unrestricted), non-porous livestock-wildlife interface (restricted by fencing), and livestock-wildlife non-interface (totally absent or control). Sera were collected from cattle aged ≥ 2 years representing both female and intact male. Sera were also collected from selected wild ungulates from Mabalauta (porous interface) and Chipinda Pools (non-interface) areas of the Gonarezhou National Park. Sera were tested for antibodies to Chlamydia abortus using a CFT. A X ² test was used to assess differences between categories and p < 0.05 was considered as significant. In cattle, the overall seroprevalence was 32.7% (327/1011; 95% CI 29.5-35.3). A significantly lower seroprevalence was recorded for the porous interface (24.2%) compared to the non-porous (42.5%) (p < 0.0001) and the non-interface (36.2%) (p = 0.001). Overall, the wet season recorded a significantly (p = 0.015) higher seroprevalence than the dry season. In wildlife, antibodies were detected in buffaloes (47.7%) and impalas (43.8%) but not in kudus. Buffaloes from Chipinda Pools (53.4%) had a significantly (p = 0.036) higher seroprevalence than those from Mabalauta (26.1%). The results established the presence of chlamydiosis in cattle and selected wildlife and that independent infections may be maintained in buffalo populations. Further studies are required to clarify chlamydiae circulating between cattle and wildlife.

Respiratory explants as a model to investigate early events of contagious bovine pleuropneumonia infection

Contagious bovine pleuropneumonia (CBPP) is a severe disease caused by Mycoplasma mycoides subsp. mycoides (Mmm). Knowledge on CBPP pathogenesis is fragmented and hampered by the limited availability of laboratory animal and in vitro models of investigation. The purpose of the present study is to assess respiratory explants as useful tools to study the early stages of CBPP. Explants were obtained from trachea, bronchi and lungs of slaughtered cattle, tested negative for Mycoplasma spp. and for the major bacterial and viral respiratory pathogens. The interaction of Mmm with explant cells was studied by immunohistochemistry (IHC), double-labelling indirect immunofluorescence (DLIIF) and laser scanning confocal microscopy (LSCM). Mmm capability to survive and proliferate within the explants was evaluated by standard microbiological procedures. Finally, the putative cellular internalization of Mmm was further investigated by the gentamicin invasion assay. IHC and DLIIF indicated that Mmm can colonize explants, showing a marked tropism for lower airways. Specifically, Mmm was detected on/inside the bronchiolar and alveolar epithelial cells, the alveolar macrophages and the endothelial cells. The interaction between Mmm and explant cells was abolished by the pre-incubation of the pathogen with bovine anti-Mmm immune sera. Mmm was able to survive and proliferate in all tracheal, bronchial and lung explants, during the entire time course of the experiments. LSCM and gentamicin invasion assay both confirmed that Mmm can enter non-phagocytic host cells. Taken together, our data supports bovine respiratory explants as a promising tool to investigate CBPP, alternative to cattle experimental infection.

Avian Viral Pathogens in Swallows, Zimbabwe : Infectious Diseases in Hirundinidae: A Risk to Swallow?

We sampled 417 swallows in a wetland ecosystem of Zimbabwe in February 2010 and October 2011. RT-PCR tests revealed circulation of avian paramyxovirus type I, avian influenza and West Nile disease viruses in these populations. We discuss the relevance of these findings in relation to what is known on the epidemiology of these viruses in these hosts and in relation to the host ecology. We conclude with recommendations to focus more research on Passeriformes in disease ecology and in particular on the hirundinidae family.

Lung lesion score system in cattle: proposal for contagious bovine pleuropneumonia

Contagious bovine pleuropneumonia (CBPP) is a severe infectious disease caused by Mycoplasma mycoides subsp. mycoides. The peculiar pathological features of CBPP make desirable the assessment of ad hoc score methods to grade the disease in the affected animals. Thus, the present work aims to assess a new lung score system for CBPP. Our results indicate that the present score system strongly correlates with that previously published by Turner and could be effectively used in CBPP-affected animals.

Seroprevalence of brucellosis in cattle and selected wildlife species at selected livestock/wildlife interface areas of the Gonarezhou National Park, Zimbabwe

A study was conducted to investigate seroprevalence and risk factors for Brucella species infection in cattle and some wildlife species in communities living at the periphery of the Great Limpopo Transfrontier Conservation Area in south eastern Zimbabwe. Three study sites were selected based on the type of livestock-wildlife interface: porous livestock-wildlife interface (unrestricted); non-porous livestock-wildlife interface (restricted by fencing); and livestock-wildlife non-interface (totally absent or control). Sera were collected from cattle aged≥2years representing both female and intact male animals. Sera were also collected from selected wild ungulates from Mabalauta (porous interface) and Chipinda (non-interface) areas of the Gonarezhou National Park. Samples were screened for Brucellaantibodies using the Rose Bengal plate test and confirmed by the complement fixation test. Data were analysed by descriptive statistics and multivariate logistic regression modelling. In cattle, brucellosis seroprevalence from all areas was 16.7% (169/1011; 95% CI: 14.5-19.2%). The porous interface recorded a significantly (p=0.03) higher seroprevalence (19.5%; 95% CI: 16.1-23.4%) compared to the non-interface area (13.0%; 95% CI: 9.2-19.9%).The odds of Brucellaseropositivity increased progressively with parity of animals and were also three times higher (OR=3.0, 2.0<OR<4.6, p<0.0001) in cows with history of abortion compared to those without.Brucella antibodies were detected in buffaloes; 20.7% (95% CI: 13.9-29.7%) form both study sites, but no antibodies were detected from impalas and kudus. These results highlight the importance of porous interface in the interspecies transmission of Brucella species and that independent infections may be maintained in buffalo populations. Thus, brucellosis control aimed at limiting animal inter-species mixing may help reduce the risk of human brucellosis in interface areas. Further studies should aim at establishing subspecies identity and direction of possible transmission of brucellosis between wildlife and livestock.

Coxiella burnetii in central Italy: novel genotypes are circulating in cattle and goats

Genotyping of bacteria is critical for diagnosis, treatment, and epidemiological surveillance. Coxiella burnetii, the etiological agent of Q fever, has been recognized to have a potential for bioterrorism purposes. Because few serosurveys have been conducted in Italy, there is still limited information about the distribution of this pathogen in natural conditions. In this paper, we describe the genotyping of C. burnetii strains by multispacer sequence typing (MST) detected in cattle and goat farms in the Abruzzi region of Italy. Biological samples (milk, aborted fetus) positive for C. burnetii DNA were sequenced in the spacer regions and compared with those already publicly available ( http://ifr48.timone.univ-mrs.fr/MST_Coxiella/mst/group_detail ). The MST profile of C. burnetii detected in milk samples demonstrated the presence of a new allele, whereas the C. burnetii spacer sequences from fetus and milk goat samples displayed a new allelic combination. The results suggest the circulation of novel genotypes of C. burnetii in Italy.

African horse sickness outbreaks in Namibia from 2006 to 2013: clinical, pathological and molecular findings

African horse sickness (AHS) is a vector‑borne viral disease of equids, endemic in Sub‑Saharan Africa. This article reports the clinic‑pathological and laboratory findings observed in the framework of passive surveillance during the AHS outbreaks which occurred in Namibia between 2006 and 2013. This study was conducted in the framework of the collaboration among the Istituto Zooprofilattico Sperimentale dell'Abruzzo e del Molise (Teramo, Italy), the Namibian Ministry of Agriculture Water and Forestry, and the Namibian National Veterinary Association. A total of 92 horses were investigated, showing different clinical form of AHS: peracute/acute (n = 43), sub‑acute (n = 21) and mild AHS fever (n = 19). Clinical data were not available for 9 horses, because they were found dead. Pathological findings have been recorded for 35 horses. At necropsy, pulmonary and subcutaneous oedema, haemorrhages and enlargement of lymph nodes were mainly observed. Diagnosis was confirmed by laboratory testing, AHS virus (AHSV) was isolated from 50 horses and the identified serotypes were: 1, 2, 4, 6, 7, 8, and 9. The phylogenetic analysis of the S10 genome sequences segregated the Namibian AHSV strains in the same clusters of those circulating in South Africa in recent years. The description of AHS clinical, pathological, and laboratory features of AHS provided in this article is of value for differential diagnosis and control of AHS, especially in areas currently free from this disease.

Bluetongue virus surveillance in the Islamic Republic of Mauritania: Is serotype 26 circulating among cattle and dromedaries?

In March 2013, EDTA-blood and serum samples were collected from 119 cattle and 159 dromedaries at the slaughterhouse of Nouakchott, the capital city of the Islamic Republic of Mauritania. Serum samples were screened for the presence of Bluetongue (BT) antibodies by competitive ELISA (cELISA). Positive samples were then tested by serum-neutralization (SN) to determine BTV serotype. RNA from blood samples was first tested by a genus-specific quantitative RT-PCR assay which is able to detect all 27 existing BTV serotypes (RT-qPCR1-27). Positive samples were further screened by a RT-qPCR assay which, instead, is able to detect the classical 24 BTV serotypes only (RT-qPCR1-24). Of the 278 serum samples tested, 177 (mean=63.7%; 95% CI: 57.9%-69.1%) resulted positive by cELISA. Of these, 69 were from cattle (mean=58.0%; 95% CI: 49.0%-66.5%) and 108 from dromedaries (mean=67.9%; 95% CI: 60.3%-74.7%). BTV-26 neutralizing antibodies were by far the most frequently found as they were detected in 146 animals with titres ranging from 1:10 to 1:80. Out of 278 blood samples, 25 (mean=9.0%; 95% CI: 6.2%-12.9%) were found positive for BTV by RT-qPCR1-27, 20 (mean=16.8%; 95% CI: 11.2%-24.6%) were from cattle and 5 (mean=3.1%; 95% CI: 1.4%-7.1%) from dromedaries. When tested by RT-qPCR1-24 the 25 BTV positive samples were negative. Unfortunately, no genetic information by molecular typing or by next generation sequencing has been obtained as for the very low levels of RNA in the blood samples.

Orbivirus detection from Culicoides collected on African horse sickness outbreaks in Namibia

African horse sickness (AHS), a non-contagious infectious disease caused by a RNA virus in the Orbivirus genus within the Reoviridae family affecting all equids, is endemic in sub-Saharan Africa. The virus is transmitted by some species of biting midges in the genus Culicoides (Diptera: Ceratopogonidae). In April 2011, 8 Culicoides collections were performed in 6 districts of 4 regions of the Republic of Namibia (Africa), all within a 400 km radious from the capital Windhoek. Six farms - Khomas (Windhoek and Steinhausen), Erongo (Karibib and Omaruru), Otjozondjupa (Okahandja), and Omaheke (Gobabis) involved in the AHS outbreaks, were sampled. Overall 194,211 Culicoides were collected and identified. Culicoides imicola was largely the most abundant species at all farms (99.4%). A total of 18,687 parous and gravid Culicoides females were assayed for AHS virus (AHSV) by real time RT-PCR. Of the 248 assayed pools, 227 consisted of C. imicola, 13 of Culicoides pycnostictus and 5 of Schultzei complex. Only 1 pool each of Culicoides nivosus, Culicoides leucostictus, and Culicoides tropicalis was assayed. Of the 248 pools examined by real time RT-PCR, 81 tested positive for AHSV, all consisting of C. imicola collected at Omaruru, resulting in a field vector infection rate of 0.91%. No viable AHSV could be isolated from 88 of the tested pools (n = 1,463). However, bluetongue virus (BTV) serotype-1 and 10 were isolated from 3 of these pools, each consisting of 100 C. imicola collected at Windhoek. The present study confirms the relative low infection prevalence in field collected Culicoides and the strict relationship between the high abundance of C. imicola and outbreaks of AHSV.

Rift Valley Fever Virus among Wild Ruminants, Etosha National Park, Namibia, 2011

After a May 2011 outbreak of Rift Valley fever among livestock northeast of Etosha National Park, Namibia, wild ruminants in the park were tested for the virus. Antibodies were detected in springbok, wildebeest, and black-faced impala, and viral RNA was detected in springbok. Seroprevalence was high, and immune response was long lasting.

MLVA as an Epidemiological Tool To Trace Back Brucella melitensis Biovar 1 Re-Emergence in Italy

Brucellosis is an important zoonosis caused by Brucella spp., still prevalent in most areas of the world. Brucellosis control in animals is the key to protect humans. The knowledge of Brucella spp. prevailing genotypes in a territory represents an important epidemiological tool to formulate policies and strategies for disease control and to trace back the introduction of new strains previously considered as exotic. In the last years, multiple-locus variable number tandem repeat analysis (MLVA) has been proposed as complementary to classical biotyping methods. MLVA may add important information to the classical epidemiological investigation techniques, to help in tracing back sources of infection in brucellosis outbreaks. Sardinia is an Italian region officially free from sheep and goats brucellosis since 1998. In 2011, Brucella melitensis biovar 1, a biotype not reported in Italy since 1995, was isolated in one flock in the region. The genotyping MLVA-16 showed that isolates belonged to a rare American lineage, confirming it was introduced from other countries. The strain was considered as probably originating from Spain, where this lineage is endemic. BrucellaMLVA-16 has been proved to be useful to analyse the epidemiological correlation of strains enabling to trace its geographic origin by comparing their previously reported genetic patterns.

Rift Valley fever in Namibia, 2010

During May-July 2010 in Namibia, outbreaks of Rift Valley fever were reported to the National Veterinary Service. Analysis of animal specimens confirmed virus circulation on 7 farms. Molecular characterization showed that all outbreaks were caused by a strain of Rift Valley fever virus closely related to virus strains responsible for outbreaks in South Africa during 2009-2010.

Recent observations on site reactions in cattle to vaccination against contagious bovine pleuropneumonia (CBPP) using T1/44 vaccine in Zambia

Contagious bovine pleuropneumonia (CBPP), a highly infectious and fatal disease of cattle present in many countries in sub-Saharan Africa, is usually controlled by mass vaccinations. However, vaccination against CBPP is known to cause site reactions in a percentage of cattle especially in primary vaccinations. In Zambia, a record of site reactions was kept for seven consecutive years from 2005 to 2011 to establish the level of the problem. In some areas, after 3 years of consecutive vaccination campaigns, immunization could not be implemented for a period of 2 years because of logistical difficulties or owner resistance. Whereas in the three preceding years when animals were vaccinated annually, site reactions were in the range of 6.2%; on resumption of vaccination in the herds that had not been immunized for 2 years, site reactions averaged 21.3%. This data shows that the T1/44 vaccine may cause severe local reactions in cattle if there is any break in annual vaccinations. It is therefore important for authorities to ensure that the cattle at risk of contracting CBPP are regularly vaccinated to avoid discouraging farmers from presenting their animals.

Prevalence of brucellosis in dairy cattle from the main dairy farming regions of Eritrea

In order to get a reliable estimate of brucellosis prevalence in Eritrean dairy cattle, a cross-sectional study was carried out in 2009. The survey considered the sub-population of dairy cattle reared in modern small- and medium-sized farms. Samples were screened with the Rose Bengal test (RBT) and positive cases were confirmed with the complement fixation test (CFT). A total of 2.77%(417/15 049; Credibility Interval CI: 2.52% - 3.05%) of the animals tested in this study were positive for antibodies to Brucellaspecies, with a variable and generally low distribution of positive animals at regional level. The highest seroprevalence was found in the Maekel region (5.15%; CI: 4.58% - 5.80%), followed by the Debub (1.99%; CI: 1.59% - 2.50%) and Gash-Barka (1.71%; CI: 1.34% - 2.20%) regions. Seroprevalence at sub-regional levels was also generally low, except for two sub-regions of Debub and the sub-region Haicota from the Gash-Barka region. Seroprevalence was high and more uniformly distributed in the Maekel region, namely in the Asmara, Berik and Serejeka sub-regions. Considering the overall low brucellosis prevalence in the country, as identified by the present study, a brucellosis eradication programme for dairy farms using a test-and-slaughter policy would be possible. However, to encourage the voluntary participation of farmers to the programme and to raise their awareness of the risks related to the disease for animals and humans, an extensive public awareness campaign should be carefully considered, as well as strict and mandatory dairy movement control.

One test microbial diagnostic microarray for identification of Mycoplasma mycoides subsp. mycoides and other Mycoplasma species

The present study describes the use of microarray technology for rapid identification and differentiation of Mycoplasma mycoides subsp. mycoides from other mycoplasmas that may be pathogenic to ruminants, including those of the Mycoplasma mycoides cluster, genetically and antigenically strictly correlated with Mycoplasma mycoides subsp. mycoides. A microarray containing genetic sequences of 55 different bacterial species from Acholeplasma, Mycoplasma, Spiroplasma and Ureaplasma genera was constructed. Sequences to genes of interest were collected in FASTA format from NCBI. The collected sequences were processed with OligoPicker software. Oligonucleotides were then checked for their selectivity with BLAST searches in GenBank. The microarray was tested with ATCC/NCTC strains of Mycoplasma spp. of veterinary importance in ruminants including Mycoplasma belonging to the mycoides cluster as well as Mycoplasma mycoides subsp. mycoides and Mycoplasma mycoides subsp. capri field strains. The results showed that but one ATCC/NCTC reference strains hybridized with their species-specific sequences showed a profile/signature different and distinct from each other. The heat-map of the hybridization results for the nine genes interrogated for Mycoplasma mycoides subsp. mycoides demonstrated that the reference strain Mycoplasma mycoides subsp mycoides PG1 was positive for all of the gene sequences spotted on the microarray. CBPP field, vaccine and reference strains were all typed to be M. mycoides subsp. mycoides, and seven of the nine strains gave positive hybridization results for all of the nine genes. Two Italian strains were negative for some of the genes. Comparison with non-Mycoplasma mycoides subsp. mycoides reference strains showed some positive signals or considerable homology to Mycoplasma mycoides subsp. mycoides genes. As expected, some correlations were observed between the strictly genetically and antigenically correlated Mycoplasma mycoides subsp. mycoides and Mycoplasma mycoides subsp. capri strains. Specifically, we observed that some Italian Mycoplasma mycoides subsp. mycoides strains were positive for two out of the three Mycoplasma mycoides subsp. capri genes, differently from what has been observed for other European or African Mycoplasma mycoides subsp. mycoides strains. This study highlighted the use of microarray technology as a simple and effective method for a single-step identification and differentiation of Mycoplasma mycoides subsp. mycoides from other mycoplasmas that may be pathogenic to ruminants, including those of the Mycoplasma mycoides cluster, genetically and antigenically strictly correlated with Mycoplasma mycoides subsp. mycoides. The opportunity to discriminate several mycoplasmas in a single analysis enhances diagnostic rapidity and may represent a useful tool to screen occasionally mycoplasmas affecting animal farming in territories where diagnostic laboratory support is limited. The heat-map of the hybridization results of the comparative genomic hybridizations DNA-designed chip clearly indicates that the microarray performs well for the identification of the tested Mycoplasma mycoides subsp. mycoides reference and field strains, discriminating them from other mycoplasmas.

Private sector involvement in the control of contagious bovine pleuropneumonia (CBPP) in the Kazungula district of Zambia benefitted the community and the control strategy

Contagious bovine pleuropneumonia (CBPP) is a disease of economic importance that is widely distributed in sub-Saharan African and contributes significantly to cattle morbidity and mortality. Lack of resources to implement eradication measures has led to the disease becoming endemic in most areas in sub-Saharan Africa where governments have little resources and the majority of the people are poor. Usually, control and eradication of such diseases as CBPP is treated as a public good by governments and to achieve this, governments are usually assisted by nongovernment organisations, bilateral government programmes and international donors. The private sector, which usually is companies that run businesses to make profit, although not very well established in sub-Saharan Africa could play a big role in the eradication of CBPP in the region. This could play a dual role of promoting investment and also eradicate livestock diseases which have proved a menace in the livestock sector. This paper highlights the role played by the private sector in the control of CBPP in Zambia.

Diagnosis of dourine in outbreaks in Italy

Dourine is trypanosomosis that affects equids, it's mainly sexually transmitted. The disease was first eradicated in Italy in the 1940s, but there was then a serious epidemic in the mid-70s. After sporadic reports at the end of the 1990s, in May 2011 it was reported once more. Clinical diagnosis of dourine can be complex, as clinical signs and gross lesions are not always present. Direct laboratory diagnosis is also problematic, given the low number of parasites normally present in infected tissues and the mild, short-lasting parasitaemia. This article describes the epidemiological, clinical and laboratory data enabling confirmation of the suspicion of dourine in Italy in the 2011 epidemic.

Bluetongue serotype 2 and 9 modified live vaccine viruses as causative agents of abortion in livestock: a retrospective analysis in Italy

The recent outbreak caused by Schmallenberg virus, which affected sheep, goats and cattle in Europe, highlighted the importance of having a robust surveillance plan capable of monitoring abortions and malformations in the livestock offspring. In this context, bluetongue viruses (BTVs) represented and represent one of the major threats to the European livestock industry. Aiming to improve the understanding on BTV cross placental transmission and serotype involvement, in this retrospective study foetal spleens and/or brains of 663 ovines, 429 bovines, 155 goats and 17 buffaloes were tested for the presence of BTV by virus isolation. BTV vaccine strains were isolated from 31 foetuses (2.4%; 95% CI: 1.7-3.4%): 24 (3.6%; 95% CI: 2.4-5.3%) from ovine foetal tissues; 6 (1.4%; 95% CI: 0.6-3.0%) from bovine foetal tissues and 1 (0.6%; 95% CI: 0.2-3.5%) from the spleen of a caprine foetus. All foetuses were from animals vaccinated with either BTV-2 or BTV-2, and BTV-9 modified live vaccines (MLVs) produced by Onderstepoort Biological Products (OBP), South Africa. Among the 31 isolated vaccine strains, serotype 9 (n = 28) was more frequently isolated (P < 0.05) than serotype 2 (n = 3). In two cases infectious vaccine strains were found in the foetal tissues 2 months after the vaccine administration. Other pathogens known to be causative agents of abortion in ruminants were not detected nor isolated. This study demonstrates, for the first time, that BTV-2 and BTV-9 vaccine strains are able to cross the placental barrier of sheep, cattle and goats. BTV-2 and BTV-9 vaccine strains are able to infect foetuses and cause abortions or malformations depending on the period of pregnancy at the time of vaccination.

Laboratory information management system: an example of international cooperation in Namibia

The authors describe the project undertaken by the Istituto G. Caporale to provide a laboratory information management system (LIMS) to the Central Veterinary Laboratory (CVL) in Windhoek, Namibia. This robust laboratory management tool satisfies Namibia's information obligations under international quality standard ISO 17025:2005. The Laboratory Information Management System (LIMS) for Africa was designed to collect and manage all necessary information on samples, tests and test results. The system involves the entry of sample data on arrival, as required by Namibian sampling plans, the tracking of samples through the various sections of the CVL, the collection of test results, generation of test reports and monitoring of outbreaks through data interrogation functions, eliminating multiple registrations of the same data on paper records. It is a fundamental component of the Namibian veterinary information system.

Plasma levels of TNF-α, IFN-γ, IL-4 and IL-10 during a course of experimental contagious bovine pleuropneumonia

Background

Contagious Bovine Pleuropneumonia (CBPP), caused by Mycoplasma mycoides subsp. mycoides, is widespread in sub-Saharan Africa. The current live vaccine T1/44 has limited efficacy and occasionally leads to severe side effects in the animals. A better understanding of the immune responses triggered by Mycoplasma mycoides subsp. mycoides and their role in disease progression will help to facilitate the design of a rational vaccine. Currently, knowledge of cytokines involved in immunity and immunopathology in CBPP is rather limited. The aim of this study was to characterize the in vivo plasma concentrations of the cytokines TNF-α, IFN-γ, IL-4, IL-10 and the overall role of CD4⁺ T cells in the development of cytokine levels during a primary infection. Plasma cytokine concentrations in two groups of cattle (CD4⁺ T cell-depleted and non-depleted cattle) experimentally infected with Mycoplasma mycoides subsp. mycoides were measured and their relationship to the clinical outcomes was investigated.

Results

Plasma cytokine concentrations varied between animals in each group. Depletion of CD4⁺ T cells did not induce significant changes in plasma levels of TNF-α, IL-4, and IL-10, suggesting a minor role of CD4⁺ T cells in regulation or production of the three cytokines during the time window of depletion (1-2 weeks post depletion). Unexpectedly, the IFN-γ concentrations were slightly, but statistically significantly higher in the depleted group (p < 0.05) between week three and four post infection. Three CD4⁺ T cell-depleted animals that experienced severe disease, had high levels of TNF-α and IFN-γ. Only one severely diseased non-depleted animal showed a high serum concentration of IL-4 post infection.

Conclusions

Comparison of most severely diseased animals, which had to be euthanized prior to the expected date, versus less severe diseased animals, irrespective of the depletion status, suggested that high TNF-α levels are correlated with more severe pathology in concomitance with high IFN-γ levels.

The first International Standard anti-Brucella melitensis Serum

The World Organisation for Animal Health (OIE) requested an International Standard anti-Brucella melitensis Serum (ISaBmS) to standardise diagnostic tests and reagents for sheep and goats. The agreed criteria were the highest dilution (in negative serum) of the standard which must give a positive result and the lowest dilution (in negative serum) which must simultaneously give a negative result. The two dilutions for each assay were, respectively: indirect enzyme-linked immunosorbent assay (iELISA) 1/64 and 1/750, competitive ELISA (cELISA) 1/8 and 1/300, fluorescent polarisation assay (FPA) 1/16 and 1/200, Rose Bengal test (RBT) 1/16 and 1/200. The OIE International Standard Serum (OIEISS) will remain the primary standard for the RBT; the ISaBmS is an additional standard. It was impossible to set criteria for the complement fixation test, therefore the OIEISS will remain the primary standard. The ISaBmS can be used to standardise iELISA, cELISA and FPA to diagnose sheep and goat brucellosis. This standard should facilitate harmonisation of tests used for brucellosis surveillance and international trade in these species.

A clinical case of dourine in an outbreak in Italy

In May 2011, dourine was reported in Italy following the declaration of a positive result observed in a stallion undergoing routine testing for stud purposes. Clinical signs, anatomo-histopathological findings and laboratory results that resulted in the confirmation of diagnosis of dourine in a clinically affected mare, which was the likely source of infection in the stallion, are described.

Contagious bovine pleuropneumonia: humoral and pathological events in cattle infected by endotracheal intubation or by exposure to infected animals

Results of trials in which cattle were infected by endotracheal intubation of Mycoplasma mycoides var. mycoides small colony (MmmSC) cultures or by contact exposure to animals affected by contagious bovine pleuropneumonia (CBPP) are numerous. However, an analysis of the effects of the two different routes of infection on disease outcome is lacking. This study analyses the disease outcome in cattle infected by the two methodologies. Data originate from two controlled trials conducted in Namibia under field conditions. Intubation appears to be responsible for chronic evolution of the disease while in-contact infected animals develop more severe infection inducing mortality. Our results seem to suggest that the mode of infection may condition the disease outcome and should be taken into consideration in studies on the pathogenesis of CBPP.

Standardisation of an indirect enzyme-linked immunosorbent assay for the detection of Brucella antibodies in milk from water buffalo (Bubalus bubalis) in Italy

An indirect enzyme-linked immunosorbent assay (ELISA) was evaluated for the detection of Brucella antibodies in milk from water buffalo (Bubalus bubalis Linnaeus, 1758). The test accuracy was evaluated on milk samples from the Campania Region in Italy. A total of 100 negative samples were collected from 10 officially brucellosis-free herds in Salerno Province, while 30 positive samples were collected from 3 herds in Caserta Province, where animals gave positive results to the official tests and it was here that Brucella abortus biovar 1 had been isolated. Test sensitivity was 100%, with a confidence interval (CI) of 90.8%-100%, while specificity was 98% (CI 93%-99.4%) on individual milk samples. To simulate bulk milk samples from herds infected at various levels of infection, dilutions from 1:10 to 1:100 of positive milk samples in negative milk were also used. The probability of detecting antibodies in positive milk samples was higher than 50% up to a dilution of 1:50 in negative milk. Considering the average national water buffalo herd size, the probability of identifying infection in a water buffalo herd by bulk milk testing is 50% (CI 33.1%-66.9%) in the worst case scenario of a single infected animal contributing to the bulk milk.

Preliminary report of transfrontier disease surveillance in free-ranging buffalo in the Caprivi Strip, Namibia

A capture operation to ascertain the health status of free-ranging buffalo (Syncerus caffer) from six areas in the Caprivi Strip in the north-east corner of Namibia is described. In-depth reports on buffalo capture operations and their cost, with detailed descriptions of diseases for research purposes, sampling techniques, field processing of samples and laboratory-related costs are still lacking in the literature. This paper describes materials, methods and the related costs of a disease surveillance operation conducted among buffalo in Namibia. The survey attempted to provide information designed to improve the control of infectious diseases in the Caprivi Strip, a key area bordering Angola, Zambia, Botswana and Zimbabwe.

Experimental infection of goats with an unusual strain of Mycoplasma mycoides subsp. capri isolated in Jordan: comparison of different diagnostic methods

Ten goats were experimentally infected with a Mycoplasma identified by biomolecular methods as Mycoplasma mycoides subsp. capri, strain Irbid which was isolated from goats in an outbreak of contagious agalactia in north Jordan and defined as 'unusual', due to its serological characteristics. Two groups of goats infected by the endotracheal route and by aerosol, respectively, were placed in contact with a third group of naive animals. Six weeks after infection, some animals from both the infected and contact groups presented fever and nasal discharge, followed by severe respiratory signs and polyarthritis. Organs were taken from animals that died during the trial or those that were sacrificed at the end of the trial. The results of microbiological isolation and immunohistochemical tests conducted on the organs were compared after a description of the clinical picture and anatomopathological and histopathological signs.

Efficacy of Brucella abortus vaccine strain RB51 compared to the reference vaccine Brucella abortus strain 19 in water buffalo

Approximately 250,000 water buffalo (Bubalus bubalis) live in the Campania region of southern Italy where the breeding of this species is very popular. Of these animals, almost 150,000 are concentrated in the Caserta province where the prevalence of Brucella abortus in this species represents approximately 20% at herd level. The Italian brucellosis eradication programme provides a slaughter and vaccination strategy for this province. B. abortus strain RB51 (RB51) has become the official vaccine for the prevention of brucellosis in cattle in several countries. The aim of this study was to evaluate the efficacy of RB51 in water buffalo compared to the B. abortus S19 vaccine (S19). The study was performed in accordance with a protocol described in mice. Female buffalo aged five months were inoculated. Five received a RB51 dosage on two occasions that was three times greater than that approved for use in cattle and a booster after one month, five received B. abortus S19 vaccine at the standard dosage and three controls received a phosphate buffer solution. Buffalo were then challenged with a virulent B. abortus strain 544 thirty days post vaccination. Antibodies that developed in the five animals vaccinated with RB51 were not detected by the Rose Bengal test or complement fixation test (CFT) and were also tested by CFT prepared with RB51 antigen. After culling, B. abortus was cultured from the spleen, retropharyngeal and supra-mammary lymph nodes. A statistical evaluation was performed to assess the immunogenicity values obtained in buffalo vaccinated with S19, compared to those obtained in buffalo vaccinated with the RB51 vaccine and in the unvaccinated control group.

African horse sickness: a description of outbreaks in Namibia

African horse sickness is a vector-transmitted viral disease that affects equidae. The authors report cases of disease that occurred in Namibia between 2006 and 2008. These were recorded by staff of the Istituto Zooprofilattico Sperimentale dell'Abruzzo e del Molise 'G. Caporale' and the Central Veterinary Laboratory in Windhoek. All cases described were confirmed by laboratory testing. This study received the support of Namibian state and private veterinarians and horse breeders.

Namibia: an example of international cooperation in the study of emerging diseases

The Istituto Zooprofilattico Sperimentale dell'Abruzzo e del Molise 'G. Caporale' (IZS A&M) has been engaged for many years in research and studies designed to increase knowledge and expertise when dealing with 'exotic diseases' namely, those diseases which are not present in a country. To achieve these objectives, it is important to create cooperation networks with laboratories and research organisations at national and international levels. The relationship between the IZS A&M with Namibia in particular and, more recently with Botswana, are proving to be very valuable to mutual technical/scientific growth. In 2005, the National Reference Centre for the Study of Exotic Diseases set up its own Virology Laboratory at the Windhoek Central Veterinary Laboratory where the Namibian and IZS A&M personnel, working towards common goals, share diagnostic responsibilities and scientific research. The authors describe the activities involved in this joint project.

An ELISA for the evaluation of gamma interferon production in cattle vaccinated with Brucella abortus strain RB51

The results of an enzyme-linked immunosorbent assay (ELISA) implemented for the detection of gamma interferon (gamma interferon) production in cattle vaccinated with Brucella abortus strain RB51 are presented. A purified protein fraction derived from RB51 (RB51 brucellin) has been used as antigenic stimulus for whole blood. The test was evaluated for 300 days in ten heifers vaccinated at calfhood with 10 x 10(9) colony-forming units of RB51 and in five control heifers. All animals came from officially brucellosis-free herds. Vaccinated animals started to give positive results from day 17 post vaccination (pv) until day 239 pv. All vaccinated animals gave a positive reaction at least once (with a stimulation index exceeding 2.5). Nevertheless, if sampling on day 20 pv is excluded (90% of vaccinated animals gave positive results), the sensitivity of the test varies from 20% to 70%, with a 40% average. A stimulation index over 2.5 was also recorded in three control animals. The results suggest that the gamma-interferon test is not suitable for the detection of cattle vaccinated with RB51, either at the individual or at the herd level.

Clinical, humoral and IFN g responses of cattle to infection with Mycoplasma mycoides var. mycoides small colony and attempts to condition the pathogenesis of the infection

Contagious bovine pleuropneumonia (CBPP), caused by Mycoplasma mycoides var. mycoides small colony (MmmSC), is one of the most important diseases of cattle in Africa. The role of innate or acquired cell mediated and humoral immunity in conferring protection against MmmSC infection has not yet been elucidated. On the other hand, the pathological lesions caused by the aetiological agent have been considered indicative of an immunopathological process. In this study ten naïve cattle were exposed to in-contact infection with animals infected by intubation with a strain of MmmSC. Clinical signs, antibody response, IFNg release and pathological changes at necropsy were analysed and compared with the events following in-contact infection of an equal number of animals kept under daily treatment with cyclosporine for the entire observation period of 84 days. Cyclosporine is a suppressor of the immune response related to the T-cell system. Under the conditions of the experiment, cyclosporine appeared to condition the pathogenesis of CBPP by delaying the events that follow infection, bringing further support to the possibility that the immune response may have an impact on the disease outcome.

Use of geographic information systems to identify areas at risk of introducing Amblyomma variegatum and A. hebraeum to Italy

Tick-borne diseases are one of the most important obstacles to the development of livestock breeding in Africa. Among these diseases, heartwater is of significant importance, second in rank to East Coast fever. Heartwater affects wild and domestic ruminants and is caused by a micro-organism belonging to the order Rickettsiales, previously called Cowdria ruminantium and recently renamed Ehrlichia ruminantium. The disease is transmitted solely by ticks. Although the aetiology and the clinical signs have been known for a long time, epidemiology presents many aspects that have yet to be understood. Among these, the biology of the vectors, ticks of the genus Amblyomma, present many features linked to environmental conditions that affect the likelihood of disease occurrence in free countries. Sporadic reports of the presence of Amblyomma variegatum in the Mediterranean are probably due to the introduction of these ticks by migratory birds. A predictive geographic information systems (GIS) model was built using temperature and land use as predictors that influence the risk of survival in Italy of infected Amblyomma ticks possibly carried by migratory birds. The model predicts Sardinia, Sicily and the south-western part of the Italian peninsula as being the most suitable areas for the presence of A. variegatum and A. hebraeum presence. The use of GIS could be an effective tool to estimate the risk of introduction and establishment of infected Amblyomma ticks.

Pneumonia of lambs in the Abruzzo region of Italy: anatomopathological and histopathological studies and localisation of Mycoplasma ovipneumoniae

The most common forms of inflammation of the lower respiratory tract in lambs are acute enzootic pneumonia, caused mainly by Mannheimia haemolytica, chronic enzootic pneumonia (defined as 'atypical' in lambs), the aetiological of which is Mycoplasma ovipneumoniae and viral inflammation principally caused by parainfluenza virus type 3. The authors conducted anatomopathological and histopathological studies of the most commonly encountered spontaneous lung inflammations in lambs slaughtered in the Abruzzo region of Italy, with special attention to 'atypical pneumonia'. Microbiological isolations and a histopathological and immunohistochemical analysis were performed to reveal any possible correlations between causal agents and lesion patterns. Positive results for M. ovipneumoniae were compared to those for Mycoplasma isolation to evaluate the sensitivity of the two techniques. Of a total of 156 samples, 31 (19.8%) demonstrated involvement of M. ovipneumoniae, 15 (9.6%) were positive on microbiological isolation confirmed by typing with biomolecular methods and, finally, histological lesions (atypical pneumonia) were observed in the remaining 16 cases (10.2%). Of these 31 samples, 23 (14.7% of the total) demonstrated postive antigen in alveolar macrophages and giant cells on immunohistochemical testing. These data revealed the presence of chronic enzootic pneumonia in the Abruzzo area and the importance of immunohistochemistry (in combination with isolation and anatomopathological and histopathological examination) for the diagnosis of pneumonia caused by M. ovipneumoniae, as well as the high sensitivity shown by antigen marker expression, even in samples where bacterial load was limited.

The Persistence of Brucella melitensis in Experimentally Infected Ewes Through Three Reproductive Cycles

The authors studied the persistence of infection in 46 ewes experimentally infected with Brucella melitensis biovar 3 and monitored through three subsequent reproductive cycles. The entire experimental period lasted for 151 weeks. Infection of ewes and elimination of Brucella in milk, or its presence in vaginal discharges, persisted throughout the duration of the trial, as demonstrated by recurrent elimination of Brucella in milk and vaginal discharges. Brucella melitensis was recovered from the tissues of one ewe killed at the end of the trial. The strain was recovered from vaginal swabs and milk following parturition in the third reproductive cycle from an ewe that had aborted in the first cycle but was not pregnant in the second cycle. From a public health point of view, the periodical recovery of Brucella from the milk during the entire trial period illustrated that brucellosis in sheep remains a continuous occupational risk and a significant public health problem for consumers of fresh milk and milk products. That risk may persist for at least 3 years following the initial infection of the flock. Lamb antibody titres became negative in all lambs within 5 months after birth. This suggested that serological tests on lambs may have no practical diagnostic significance if performed during the first 5 months of life. Nevertheless, the birth of three infected lambs suggested that the phenomenon of latent carrier state may represent another way for B. melitensis to persist in a flock.

Use of innovative methods in the eradication of bovine tuberculosis

During final phases of eradication programmes, strains of Mycobacterium sp. not belonging to the tuberculosis complex increase their relative frequency and are responsible for positive skin test reactions. Moreover, the specificity of any indirect diagnostic test, such as the skin test, is never completely accurate, therefore even when tuberculosis infection is completely eradicated, a number of false positive reactions are to be expected. The aim of this paper is to evaluate the performances of traditional isolation/typing techniques, automatic isolation/typing techniques based on fluorimetric detection of bacterial growth (Bactec), skin tests and the -interferon test. Samples examined for the evaluation of test sensitivities originated from 154 infected animals belonging to 32 infected herds. Samples used as negative controls in the evaluation of test specificities originated from 86 animals of nine officially infection-free herds. The automatic isolation/typing technique based on fluorimetric detection of bacterial growth showed higher sensitivity than the traditional isolation typing technique. Moreover, it allowed a safer processing of bacterial cultures, decreasing the risk for laboratory workers. The observed performance of the gamma-interferon test was considered beneficial in that it increased the sensitivity of individual diagnosis within an infected herd, especially in 'problem herds', but its poor specificity did not improve detection of infected herds compared to the skin test.

Unexpected isolation of virulent Newcastle disease virus from commercial embryonated fowls' eggs

The authors report a case of causal isolation of virulent Newcastle disease virus (NDV) from embryonated eggs. The virus was isolated from uninfected chicken embryo liver and fibroblast cultures prepared from commercial embryonated fowls' eggs. A serological and virological investigation carried out on the breeders which had laid those eggs showed high titres against NDV, and virus isolation from cloacal swabs. The virus was also isolated from the progeny of the same breeders which showed no clinical signs of ND, following episodes of mortality. Vertical transmission of the virus is discussed.