Emerging Zoonotic Diseases among Pastoral Communities of Caia and Búzi Districts, Sofala, Mozambique: Evidence of Antibodies against Brucella, Leptospira, Rickettsia, and Crimean-Congo Hemorrhagic Fever Virus

Emerging zoonotic diseases are an increasing threat to public health. There is little data on the seroprevalence of zoonotic diseases among pastoralists in the country. We aim to carry out a cross-sectional study on the prevalence of major zoonotic diseases among pastoral communities in the Caia and Búzi districts. Methods: Between January and December 2018, a questionnaire was used to solicit socio-demographic data from consenting pastoralists with the collection of blood samples in the Caia and Búzi districts of the Sofala province. All samples were tested using ELISA commercial reagents for the detection of IgM antibodies against Brucella and Leptospira. Likewise, IgM and IgG antibodies against Rickettsia and CCHFV were determined using ELISA kits. Results: A total of 218 samples were tested, of which 43.5% (95/218) were from the district of Caia and 56.4% (123/218) from the Búzi district. Results from both districts showed that the seroprevalence of IgM antibodies against Brucella and Leptospira was 2.7% (6/218) and 30.3% (67/218), respectively. Positivity rates for IgM and IgG anti-Rickettsia and CCHFV were 8.7% (19/218), 2.7% (6/218), 4.1% (9/218), and 0.9% (2/218), respectively. Conclusions: Results from our study showed evidence of antibodies due to exposure to Brucella, Leptospira, Rickettsia, and CCHFV with antibodies against Leptospira and Rickettsia being the most prevalent. Hence, laboratory diagnosis of zoonotic diseases is essential in the early detection of outbreaks, the identification of silent transmission, and the etiology of non-febrile illness in a pastoral community. There is a need to develop public health interventions that will reduce the risk of transmission.

Expression and functional analysis of Brucella outer membrane protein 25 in recombinant goat pox virus.

The Capripoxvirus (CaPV) has a large double­stranded DNA genome and a restricted host­range. At present, it is being investigated as an ideal vaccine vector. In the present study, a novel recombinant goat pox virus (rGTPV) was constructed to express Brucella outer membrane protein (OMP)25, and was validated by in vitro and in vivo immunization assays. A novel rGTPV vector was created, in which the thymidine kinase gene was used as a flanking sequence, I1L was inserted as a promoter element to enhance Brucella OMP25 expression, and p7.5 as another promoter element was used to regulate guanine phosphoribosyl­transferase as a selection maker. The rGTPV vector was transfected into sheep fetal fibroblast/lamb testis cells pre­infected with GTPV G14­STV44­55 to recombine. Brucella OMP25 protein was expressed in cells by rGTPV, and activated immune reactivity to Brucella OMP25 protein, as detected by western blotting. Furthermore, rGTPV elicited, anti­Brucella­specific immunoglobulin G responses, as determined by ELISA. Mice vaccinated with rGTPV did not exhibit pathology alterations in the kidney and liver. These results suggested that the novel rGTPV was able to efficiently drive Brucella OMP25 protein expression and activate immune reactivity, and may have applications in CaPV live vector vaccines and associated research.

Detección de Brucella spp. por un sistema inmunocromatográfico comercial, en muestras ambientales cubanas

Introducción: actualmente en Cuba se desconoce la circulación de las especies de Brucella en el medio ambiente, por la inexistencia de métodos de laboratorio que permitan su identificación. Objetivos: detectar Brucella spp. en muestras ambientales cubanas aplicando un sistema inmunocromatográfico comercial. Métodos: se estudiaron 59 muestras ambientales de una zona endémica de brucelosis bovina y 50 muestras ambientales de zonas controladas de la enfermedad, durante el período diciembre de 2011 y hasta febrero de 2012. Se utilizó el sistema inmunocromatográfico directo de flujo lateral para Brucella spp. comercializado en Cuba. Resultados: el 52,5 por ciento (31/59) de las muestras ambientales de la zona endémica resultaron positivas para Brucella spp. Las muestras ambientales que presentaron el mayor porcentaje de positividad fueron el estiércol (62,5 por ciento) y las del suelo cementado (26,9 por ciento ). Predominaron las reacciones fuertemente positivas en un 74,1 por ciento (23/31). Conclusiones: el sistema inmunocromatográfico comercial detecta un elevado porcentaje de Brucella spp. en muestras ambientales de la zona endémica cubana, lo que pudiera avalar su implementación en la red de laboratorios de Salud Pública y del Instituto de Medicina Veterinaria de Cuba. Los resultados de esta investigación deben complementarse con los aislamientos de brucelas en el medio ambiente, pacientes humanos y en animales(AU)

Introduction: The circulation of Brucella species in the environment is unknown in Cuba, due to the lack of laboratory methods to identify them. Objectives: To detect Brucella spp. In Cuban environmental samples by applying a commercial immunochromatographic system. Methods: 59 environmental samples from an endemic area of ​​bovine brucellosis and 50 environmental samples from controlled areas of the disease were studied during the period December 2011 to February 2012. The direct lateral flow immunochromatographic system was used for Brucella spp. Marketed in Cuba. Results: 52.5 percent (31/59) of environmental samples from the endemic area were positive for Brucella spp. The environmental samples that presented the highest percentage of positivity were the manure (62.5 percent) and those of the cemented soil (26.9 percent). Strongly positive reactions prevailed in 74.1 percent (23/31). Conclusions: the commercial immunochromatographic system detects a high percentage of Brucella spp. In environmental samples of the Cuban endemic area, which could support its implementation in the network of Public Health laboratories and the Institute of Veterinary Medicine of Cuba. The results of this research should be complemented with the isolates of brucella in the environment, human patients and animals(AU)

Comparative whole genome analysis of six diagnostic brucellaphages.

Whole genome sequencing of six diagnostic brucellaphages, Tbilisi (Tb), Firenze (Fz), Weybridge (Wb), S708, Berkeley (Bk) and R/C, was followed with genomic comparisons including recently described genomes of the Tb phage from Mexico (TbM) and Pr phage to elucidate genomic diversity and candidate host range determinants. Comparative whole genome analysis revealed high sequence homogeneity among these brucellaphage genomes and resolved three genetic groups consistent with defined host range phenotypes. Group I was composed of Tb and Fz phages that are predominantly lytic for Brucella abortus and Brucella neotomae; Group II included Bk, R/C, and Pr phages that are lytic mainly for B. abortus, Brucella melitensis and Brucella suis; Group III was composed of Wb and S708 phages that are lytic for B. suis, B. abortus and B. neotomae. We found that the putative phage collar protein is a variable locus with features that may be contributing to the host specificities exhibited by different brucellaphage groups. The presence of several candidate host range determinants is illustrated herein for future dissection of the differential host specificity observed among these phages.

Comparative genomic analysis of two brucellaphages of distant origins.

Here, we present the first complete genome sequence of brucellaphage Tbilisi (Tb) and compared it with that of Pr, a broad host-range brucellaphage recently isolated in Mexico. The genomes consist of 41,148 bp (Tb) and 38,253 bp (Pr), they differ mainly in the region encoding structural proteins, in which the genome of Tb shows two major insertions. Both genomes share 99.87% nucleotide identity, a high percentage of identity among phages isolated at so globally distant locations and temporally different occasions. Sequence analysis revealed 57 conserved ORFs, three transcriptional terminators and four putative transcriptional promoters. The co-occurrence of an ORF encoding a putative DnaA-like protein and a putative oriC-like origin of replication was found in both brucellaphages genomes, a feature not described in any other phage genome. These elements suggest that DNA replication in brucellaphages differs from other phages, and might resemble that of bacterial chromosomes.

The characterisation of Brucella strains isolated from marine mammals.

Small Gram negative coccobacilli isolated from seals, porpoises, dolphins and from an otter road casualty were identified as Brucellae by their colonial and cell morphology, staining characteristics, biochemical activity, agglutination by monospecific antisera and susceptibility to lysis by Brucella specific bacteriophage. Their characterisation, including metabolic profiles, is described. These strains could not be assigned to recognised nomen species of the genus Brucella and it is suggested that they comprise a new nomen species to be called B. maris (sp. nov., type strain 2/94). It is further suggested the nomen species be subdivided into three biovars corresponding to their CO2 requirement, metabolic activity on galactose, dominant antigen and animal host.