Veterinaria Italiana (Journal)
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P6-05 Evaluating the OPS linkage composition for all biovar type strains of B. abortus, B. melitensis and B. suis and strains described by the WOAH for use in the production of vaccines and diagnostics
No full textThe O-polysaccharide (OPS) of smooth classical Brucella species is a critical virulence determinant, essential serodiagnostic antigen and a crucial component in two of the three vaccines described by the WOAH. Yet, despite its significance, the OPS structure has only been determined for a few (n=7) strains. For other strains the structure and approximate proportion of α1-2 or α1-3 glycosidic linkages is inferred from monoclonal antibody binding profiles; this determines the A or M dominance of strains. The genetic basis for linkage type and proportion has not been identified so cannot be inferred from sequence data or PCR. It is possible that linkage type may have a functional role for Brucella. The ratio and positioning of α1-2 or α1-3 may also play an increasing role in diagnosis and vaccine design given the advent of synthetic oligosaccharide antigens. To better characterise the OPS structure and define relative abundance of the α1-3 glycosidic linkages, we evaluated smooth type strains of B. abortus (n=10), B. melitensis (n=4) and B. suis (n=5) (including vaccine strains B. abortus S19 and B. melitensis Rev.1) and Y. enterocolitica O:9, using 1H Nuclear Magnetic Resonance (NMR). Assignments of the anomeric proton were made at chemical shifts of 5.05 ppm for α1-3 and 5.17 ppm for α1-2 linkage types. Relative abundance of linkage types was determinedas a ratio of peak heights at these chemical shifts. We compared this ratio with monoclonal antibody (Mab) binding data (determined by iELISA). Structural analysis confirmed that α1-3 glycosidic linkages are present in all evaluated Brucella stains (other than B. suis biovar 2), in line with the abundance suggested by MAb binding profiles. A finding from this work that may have a more immediate application is that the OPS from the attenuated B. abortus vaccine strain S19 showed the same glycosidic linkage composition profile as the OPS from diagnostic antigen strains B. abortus S99 and S1119-3. Strain S19 may be a less virulent and safer alternative for use as a diagnostic antigen. SDS-PAGE demonstrated that S19 has similar length OPS to S19 and S1119-3, and this may also be an important diagnostic property
P8-09 An Epidemiological Study of Brucellosis in Camels (Camelus dromedarius) in Khartoum State, Sudan
No full textA study was conducted from April to September 2012, to determine the seroprevalence and risk factors for brucellosis infection in camels (Camelus dromedarius) in Khartoum State, Sudan. A total of 415 camels in 39 herds were included in the study from four localities and blood samples were collected and screened by RBPT. Twenty four samples tested positive giving an individual animal prevalence rate of 5.8%. All RBPT positive reactors were further tested by cELISA which confirmed 21 seropositive cases out of 24 RBPT reactors (87.5%). Eighteen herds were found seropositive among the 39 herds included in the study giving a herd prevalence of 46%. In the univariate analysis there was a significant increase in seropositivity of brucellosis in camel with respect to age and herd size (P≤ 0.05). Conversely, governorate, locality, sex, feeding, type of management, type of production, contact with other camels, source of new camels, source of water, housing, contact with other ruminants and contact with dogs were not found significantly associated with brucellosis (P≥ 0.05).Multivariate analysis showed that large herd size comprising more than 20camels was significantly associated with seroprevalence of camel brucellosis (Exp B=5.660; 95% CI: 1.258 -25.463; P≤0.05). The results of the present study indicate that Brucella exists within the camel herds in KhartoumState. The disease is widely distributed among large camel herds in the State. Further studies need to be done on Brucella infection in the other ruminants to determine which measures should be followed for control of brucellosis
O7-1 Brucellosis in a farming community in central South Africa: A longitudinal cohort study (2015-2018)
No full textBrucellosis is a widespread zoonotic disease of public health importance that is often associated with occupational exposure. Despite brucellosis being considered a priority zoonotic disease in South Africa, the true incidence and prevalence of the disease in animals and humans is largely unknown. To enhance the current understanding of human brucellosis in South Africa, the persistence of Brucella antibodies and the number of new infections in a farming community were investigated. A longitudinal study was conducted in a farming community within a 40 000 km2 area in the Free State and Northern Cape provinces, South Africa. Participants (n=232) were selected from three cross-sectional studies conducted over a 36-month period from 2015-2018. Participants enrolled in at least the first and last surveys were included in the cohort. Seroprevalence was determined using an anti-Brucella IgG enzyme-linked immunosorbent assay (ELISA). Seropositive samples were tested further using an anti-Brucella IgM ELISA and immunocapture agglutination test to assess the antibody profiles. Statistical analysis was conducted using STATA v14. Of 232 participants, 87.9% (204/232) were from a farming population (people living and working on 102 domestic and game farms) and 12.1% (28/232) were (para)veterinary professionals. The median age was 39 years(interquartile range: 31-51 years) at first enrolment and 84.9% (197/232) were male. The IgG seropositivity was 13.4% (31/232), 14.2% (19/134) and 12.9% (30/232), respectively for the three surveys. Of the reactors, 83.9% (26/31) remained IgG seropositive and at least 6.5% (2/31) also had persistent IgM antibodies. Five of the participants seroconverted over the study period. This is the first longitudinal cohort study investigating human brucellosis in South Africa. A large proportion of reactors had persistent specific antibodies over the 36-month study period. Because unrecognize seroconversion was detected in the farming community, it is possible that more individuals were antibody-positive than would otherwise be reported, and that they could have ongoing infection if not treated appropriately. The findings from this study once again highlight the need to interpret serological results in light of the clinical context for the diagnosis of active brucellosisin high-risk populations especially in endemic areas
P3-11 In-vitro model of macrophages bovine cell for the characterization of pathogenic mechanisms of bovine brucellosis.
No full textBrucella infection, affecting several animal species, constitutes one of the main zoonosis worldwide with a high economic impact. Disease pathogenicity is mainly associated with the ability of Brucella to evade the host immune system by surviving inside both phagocytic and non-phagocytic cells, especially macrophages, dendritic cells and granulocytes. This leads to a chronic persistent infection, in a mechanism notyet completely characterized. The macrophages, among cells of the innate immune system, constitute the first defense line against pathogens and an important immuno-modulating determinant. For this reason, the investigation on Brucella strains behavior inside macrophages could be essential to better understand and define the pathogenic mechanisms in humans and host species. In this context, we investigated the virulence of B. melitensis and B. abortus, the Brucella strains with the highest zoonotic potential, on BoMac cells, anin vitro cellular model of bovine peripheral macrophages. This study has the purpose of characterizing the bovine-pathogen interaction and developing an in vitro system serving as a reference model of bovine brucellosis infection. We observed the internalization of both B. melitensis and B. abortus in BoMac macrophages, their survival and proliferation inside host cells up to 72h from infection. Further investigations are ongoing on host gene expression and production of pro- and anti-inflammatory cytokines to characterize the bovine macrophages immuno-modulating response in the in vitro infection model. The characterization of pathogen virulence factors and the host cells molecular response, constitute the basis for understanding infectious disease mechanisms and development of more effective tools for their control
O7-5 Human brucellosis exposure in confirmed cutaneous anthrax cases, Dien Bien, Vietnam with an update on human prevalence regionally
No full textAnthrax and brucellosis are important zoonoses worldwide. Often, they are reported separately with separate control strategies in livestock; routine vaccination for both accompanied by culling for brucellosis. The status of both diseases is poorly understood in Vietnam. In Vietnam, anthrax has been identified as a priority zoonotic disease for control in a One Health Circular (#16, 2013). Vietnam has a likely substantial, but poorly understood, brucellosis risk. There were no data available for Vietnam in the 2006 global assessment. Brucellosis rates are unknown, but the disease has been confirmed for humans and livestock, including recent genotyping in southern provinces. Here, we implemented the fluorescence polarization assay (FPA) using the Sentry 200 handheld FPA reader (Ellie Labs) and the B1002 test kits (based on an O-polysaccharide for Brucella abortus, which also reacts with B. suis and B. melitensis. We performed tests on human and animal samples. Human serum samples (collected 2011-2016) were randomly selected from the NIHE serum bank and livestock samples were provided from NCVD and NIHE (2015 - 2018); additional swine samples were provided by ILRI. We are currently running active hospital surveillance across six provinces in northern Vietnam, with 1,018 samples collected to date and 312 tested. We confirmed 1.39% human exposure to brucellosis (5/359; 95% CI: 0.045% - 3.22%). Four of those exposures were detected in Dien Bien province and two of those were confirmed cutaneous anthrax cases. The two co-infections were detected in family members from a single household in 2011 with the remaining two cases independent of each other in 2015. The fifth case was reported from Ha Nam province in 2016. These results suggest brucellosis may be widespread underappreciated/underreported in Vietnam. Preliminary results from ongoing surveillance suggest similarprevalence rates. We tested 1107 animals. While human samples were limited to northern Vietnam, animal samples were widely distributed. Domestic swine from southern Vietnam were 9.4% (17/180) seropositive. A second group of swine samples from ILRI had 2.2% seroprevalence (11/500). The remaining samples represented domestic cattle/buffaloes; all sero-negative. Our results suggest brucellosis surveillance for Vietnam is warranted and future policy might list brucellosis as reportable
R04.4 Mapping bioclimatic suitability for cattle ticks in Ecuador
No full textHard ticks affect cattle in tropical and subtropical areas across the world. In Ecuador, the main species affecting cattle are Rhipicephalus microplus and the complex Amblyomma cajennense sensu lato. Both cause economic losses to cattle farmers by decreasing milk and meat production, and transmitting pathogens. They can indirectly affect human and environmental health, due to the toxicity of acaricides used to control ticks and acaricide residues. In Ecuador as in other countries, acaricide resistance in cattle ticks has become an acute problem in cattle management. Although several studies have modelled the distribution of R. microplus and A. cajennense s.l. worldwide and in South America, suitable models for Ecuador are still lacking. Ecuador’s contrasted environment, spanning across the Andes, requires calibrating a specific model. The aim of this study was to model the distribution of R. microplus and A. cajennense s.l. in continental Ecuador using Random Forest with 19 bioclimatic variables and vapour pressure deficit (CHELSA database). In total, 2895 farms were surveyed and georeferenced between 2012 and 2015. R. microplus was present in 38.51% and A. cajennense s.l. in 16% of farms. Cross-validation values for the Random Forest models were, for R. microplus and A. cajenense s.l. respectively: accuracy = 0.97, 0.98, Sensibility = 0.97, 0.99, and Specificity = 0.96, 0.93. The final models included ten bioclimatic variables i.e. Bio 1, Bio14, Bio4, Bio12, Bio 13, Bio3, vapour pressure deficit max and min, Bio 2, and Bio 18. The predicted models showed the potential risk of the presence of R. microplus and A. cajennense s.l. distribution in continental Ecuador. We discuss the interest of these models for managing this issue at the national level, including through a better understanding of areas at risk, and better use of chemicals acaricide. This may be particularly important if cattle farming further develops in the Amazon region. We also discuss the challenge of focusing on the climatic envelope, while tick presence is also affected by management practices.
P08.6 The role of multi-species bird migration network in West Nile disease dynamics in Italy
No full textAvian migration plays a critical role in the transmission of vector-borne diseases, including West Nile Virus (WNV). WNV has become endemic in Northern Italy's Po Valley since 2008, affecting many resident bird species, and in Sardinia, where WNV circulation has been mainly reported in migratory birds. Sporadic cases have also been reported in southern Italy, and some northern regions along the Tyrrhenian coast. A comprehensive One Health approach, integrating human, terrestrial vertebrate, and entomological surveillance, is vital for the timely detection of the seasonal virus spread to applying preventive measures (Candeloro et al., 2020).
This study investigates avian migration's role in shaping the dynamics of WNV in Italy, enhancing understanding of transmission patterns. Ringing and recovery data of birds ringed in Italy (from 2008 to 2017) were retrieved from ISPRA's Italian Ringing Center.
Spatial clustering and network analysis were employed to generate and characterize the bird migration network (Lamb et al., 2019). The network included 31 spatial clusters and 71 links. Strong agreement between network metrics (In-degree, Out-degree, In-strength, Out-strength, and Betweenness) and WNV cases was observed. Clusters encompassing regions featured by the presence of endemic areas were found to be highly vulnerable or able to spread the infection. Tuscany and Lazio Regions emerged as network hubs, underlining their significant role in WNV circulation.
The Giant Strongly Connected Component (GSCC) linked the endemic area to other WNV-affected Regions. Community detection analysis highlighted connections during the spring season between northern Sardinia, Tuscany, and Abruzzi Regions, accordingly with GSCC. During summer, GSCC extended to southern Sardinia. Except for Campania, low northern-southern Italy connections correlated with fewer outbreaks observed in the latter. Dynamic measures, like Forward/Backward Reachable Set (FRS/BRS), accounted for time/direction and confirmed the previous results. BRS, during the epidemic season, showed a limited connection from the endemic area to central-southern Italy.
To explain the disease's spatial-temporal distribution, we developed a network-based stochastic SEI model, accounting for the suitability of WNV circulation, uncertainty in the timing of movements, and disease incubation period. Evaluated scenarios: 1) Disease spread within Italy from endemic areas, 2) Introduction from Africa.
Results confirmed and expanded on network analysis. In scenario 1, infection reached clusters including Sardinia, Campania, and Basilicata (30-35% simulations), despite unfavorable seasonal conditions for viral circulation at the time of exposure. Liguria showed infection during favorable conditions. In scenario 2, southern Italy (e.g., Puglia) had foreign-origin infections. Notably, northern Sardinia, in Scenario 1, showed autumn exposure pick in this scenario.
The study analysed selected bird species' migration in Italy using static, seasonal, and dynamic network analysis. Viral circulation was detected and supported by the SEI model. Concerns about data representativeness, particularly in Sicily and Sardinia, highlighting the need for broader migration data, including telemetry data
K05 Infectious water-associated diseases: the role of the environment
No full textThe concept that our health is linked to air and water quality is not new. Nor is the idea that spatial patterns in disease outbreak could hold the key to solutions. What is new is the unprecedented access to spatially-resolved environmental data, thanks to space technology: whether they be satellite-based observations of our planet, or information from smart phones, through citizen science initiatives. Such streams of data open up new avenues for exploring the links between the environment and disease outbreaks. In this talk some applications of space technology for the study of water-associated diseases will be presented, drawing on our own work as well as that of others. However, when addressing such a complex problem, satellite technology can only provide a piece of the puzzle, at best. There is a need for scientists of various disciplines to work together with health practitioners and with the citizens in vulnerable areas, to enable effective and long-lasting solutions. Such thinking is embedded in the One Health concept of World Health Organization. They can also contribute to the Sustainable Development Goals of the United Nations, especially those that relate to water
P7-02 Human brucellosis, an important however a neglected zoonotic disease: Status in occupational and non-occupational groups in Punjab (India)
No full textBrucellosis is one of the major neglected zoonotic diseases in India, and has been reported in animals and humans across almost all states of the country. Several health agencies have been working on this pathogen all over India. The Centre for One Health (COH), Guru Angad Dev Veterinary and Animal Sciences University (GADVASU) has been established with the aim to strengthen the One Health Framework to work on one health issues in India. The Centre is very actively engaged in the surveillance of antimicrobial resistance, food safety and several endemic zoonotic diseases including brucellosis. Brucellosis not only affects the health of animals but also has impact on human health especially of occupational risk groups, for example veterinarians and dairy farmers. The tertiary care hospitals are now including human brucellosis in differential diagnosis in cases of fever of unknown origin. In the present study, where in COH is rendering brucellosisdiagnostic facility to the various stakeholders in Punjab state of India, a total of 417 human blood samples were tested for Brucella agglutinins using Rose Bengal plate test and serum tube agglutination (STA) tests during the period 2020-22. The blood samples were of the veterinary personnel, dairy farmers who approached COH for brucellosis testing and of the patients with history of fever of unknown origin referred bythe multispecialty hospital. Out of 417 samples, 85 (20.3%) were found positive for antibodies to Brucella with STA titre ranged from 160-10240 IU. Forty-one out of 161 patients referred by multi-speciality hospital for brucellosis were seroprevalence; majority of them belong to non-occupationally exposed population. The findings revealed the endemic status of brucellosis in the state, thus reflecting the continuous exposure of human to this zoonotic disease, and indicates the presence of infection in both occupational as well as non-occupational groups. Veterinarians and farmers most of the time due to nature of their work have the awareness about this pathogen, but non-occupational groups need to be educated about the transmission, prevention and control of this disease
O2-5 Whole genome based tools in epidemiological surveillance of Brucella abortus, Brucella melitensis and Brucella suis bv2 in Italy in the last decade.
No full textBrucellosis is one of the most important zoonotic diseases in the Mediterranean basin. In Italy, Brucella abortus and B. melitensis, prevalent in the southern regions despite the ongoing eradication campaign, continue to pose public health risk and cause significant economic losses. In this work we use genomic tools to study the epidemiology of B. abortus, B. melitensis and B. suis bv2 in Italy over the last decade. We sequenced over 1,300 Brucella strains collected between 2011 and 2021. The sequences were typed using whole genome sequencing (WGS)-based methods, including single nucleotide polymorphism (SNP) and core genome multilocus sequence typing (cgMLST) and clusters of genetically related strains were identified. WGS typing results demonstrated the presence of three large clusters of B. abortus, corresponding to diverse sequence types. ST-30 was dominant in Sicily, while ST-1 and ST-2 were found mostly in mainland Italy. ST-1 strains, all assigned to biovar 1 were collected primarily from buffalo and largely restricted to Campania region. These strains formed a tight genomic cluster that has persisted in the region for the entire decade. B. melitensis was predominantly found in the south, with the highest prevalence in Sicily and Calabria. While in these regions we observed weak geographical segregation of the genotypes, the incursions of B. melitensis in the northern regions were generally caused by single clone introductions. Half of the cases of human brucellosis could be attributed to the locally circulating B. melitensis strains, while the others were mainly imported from North Africa. The population of B. suis bv2 from the wild boars and pigs in Italy was grouped in several lineages. Central European lineage, confined to the northwestern regions, and Eastern European lineage, found along the Apennine mountain ridge, both contained highly clonal strains suggesting that they arose from single introduction events, likely linked to the wild boar repopulation campaigns. Our study demonstrates that a large number of Brucella clones persisted over many years in Italy, escaping the control measures imposed in the eradication programmes. Integrating WGS analysis of Brucella strains with the current control strategies would be vital for more effective eradication campaign in Italy