Pathogens

Research

11 pages, 1388 KiB

Open AccessEditor’s ChoiceArticle

Modelling Human Brucellosis Based on Infection Rate and Vaccination Coverage of Sheep and Goats

by Georgios Dougas, Aristomenis Katsiolis, Maria Linou, Polychronis Kostoulas and Charalambos Billinis

Pathogens 2022, 11(2), 167; https://doi.org/10.3390/pathogens11020167 - 27 Jan 2022

Cited by 6 | Viewed by 2640

Abstract

In this study, the vaccination coverage, serological sampling and infection rate of sheep and goats were evaluated as predictors for the modeling of human brucellosis in Greece. The human brucellosis disease frequency per local regional unit (RU) varied significantly (RR90) among consecutive years. [...] Read more.

In this study, the vaccination coverage, serological sampling and infection rate of sheep and goats were evaluated as predictors for the modeling of human brucellosis in Greece. The human brucellosis disease frequency per local regional unit (RU) varied significantly (RR90) among consecutive years. The notification rate was higher (p < 0.001) in the RUs with implementation of vaccination in sheep and goats (vaccination zone—VZ) with a median of 1.4 (IQR 0.0–3.1) compared with the RUs of the eradication zone (EZ) with a median of 0.0 (IQR 0.0–0.0). In VZ, the increased frequency of human cases was associated with delayed vaccine administration (estimate: 0.14 (0.04; 0.29), p = 0.03) and higher vaccination coverage of the animals (estimate: −0.349 (−0.72; −0.07), p < 0.01). However, the flock sampling rate was highly heterogenous among RUs (IQR 10.56–52.93), and inconsistent within RUs throughout the period of the study 2013–2017 (p = 0.001), limiting the reliable estimation of the infection rate in livestock and the design of an integrated One Health model for human disease. Full article

(This article belongs to the Special Issue Brucella Species and Brucella melitensis)

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12 pages, 1012 KiB

Open AccessArticle

Progressive Area Elimination of Bovine Brucellosis, 2013–2018, in Gauteng Province, South Africa: Evaluation Using Laboratory Test Reports

by Krpasha Govindasamy, Eric M. C. Etter, Peter Geertsma and Peter N. Thompson

Pathogens 2021, 10(12), 1595; https://doi.org/10.3390/pathogens10121595 - 9 Dec 2021

Cited by 3 | Viewed by 2993

Abstract

Bovine brucellosis is a zoonotic disease of global public health and economic importance. South Africa has had a national bovine brucellosis eradication scheme since 1979; however, no published report on elimination progress from any province exists. We analysed laboratory test results of all [...] Read more.

Bovine brucellosis is a zoonotic disease of global public health and economic importance. South Africa has had a national bovine brucellosis eradication scheme since 1979; however, no published report on elimination progress from any province exists. We analysed laboratory test results of all cattle herds participating in the Gauteng Provincial Veterinary Services’ eradication scheme between 2013 and 2018. Herd reactor status and within-herd seroprevalence, modelled using mixed-effects logistic and negative binomial regression models, respectively, showed no significant change over the period. However, provincial State Vet Areas, Randfontein (OR = 1.6; 95% CI: 1.2–2.1; p < 0.001) and Germiston (OR = 1.9; 95% CI: 1.5–2.5, p = 0.008) had higher odds of reactor herds than the Pretoria Area and within-herd prevalence count ratios for these areas were 1.5-fold greater than the Pretoria State Vet Area (p < 0.001). Reactor herds were associated with increased herd size (p < 0.001) and larger herd sizes were associated with lower within-herd prevalence (p < 0.001). Despite no evidence of significant progress toward bovine brucellosis elimination in Gauteng province, variability in bovine brucellosis prevalence between State Vet Areas exists. A public health and farmer-supported strategy of ongoing district-based surveillance and cattle vaccination targeting small- to medium-sized herds combined with compulsory test and slaughter of reactors in larger herds is recommended for the province. Full article

(This article belongs to the Special Issue Brucella Species and Brucella melitensis)

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16 pages, 1123 KiB

Open AccessArticle

Bovine Brucellosis in Gauteng, South Africa: Seroprevalence amongst Cattle Handlers and Variables Associated with Seropositive Cattle Herds, 2014–2016

by Krpasha Govindasamy, Peter N. Thompson, Bernice N. Harris, Jennifer Rossouw, Darrell A. Abernethy and Eric M. C. Etter

Pathogens 2021, 10(12), 1547; https://doi.org/10.3390/pathogens10121547 - 26 Nov 2021

Cited by 4 | Viewed by 2909

Abstract

In South Africa, the prevalence of cattle handler exposure to Brucella on cattle farms is unknown and risk factors and cattle symptoms associated with infected cattle herds are unavailable. To address this gap, a case-control study of cattle herds was conducted in Gauteng [...] Read more.

In South Africa, the prevalence of cattle handler exposure to Brucella on cattle farms is unknown and risk factors and cattle symptoms associated with infected cattle herds are unavailable. To address this gap, a case-control study of cattle herds was conducted in Gauteng province and farm workers and veterinary officials were tested for exposure to Brucella. Seroprevalence amongst farm workers exposed to case herds ranged from 4.0% (BrucellaCapt^®) to 16.7% (IgG ELISA^®), compared to those exposed to control herds, where seroprevalence ranged from 1.9% (BrucellaCapt^®) to 5.7% (IgG ELISA^®). Seroprevalence amongst veterinary officials was significantly greater compared to farm workers exposed to case herds for the outcome RBT+ IgM- IgG+ (OR = 11.1, 95% CI: 2.5–49.9, p = 0.002) and RBT- IgM- IgG+ (OR = 6.3, 95% CI: 2.3–17.3, p < 0.001). Risk factors associated with being an infected herd were: being a government-sponsored farm vs. private farm (OR 4.0; 95% CI: 1.4–11.3; p = 0.009), beef vs. dairy herd (OR 7.9; 95% CI: 1.4–44.9; p = 0.020), open vs. closed herd (OR 3.3; 95% CI: 1.1–10.4; p = 0.038) and the presence of antelope on the farm (OR 29.4; 95% CI: 4.0–218.2; p = 0.001). Abortions (OR = 5.1; 95% CI: 2.0–13.3; p < 0.001), weak calves in the herd (OR = 8.0; 95% CI: 2.6–24.4; p < 0.001), reduction in number of calves born (OR = 9.0; 95% CI: 2.1–43.6; p < 0.001), reduction in conception rate (OR = 3.9; 95% CI: 0.8–18.3; p = 0.046), hygromas in cattle (p = 0.011) and farmers reporting brucellosis-like symptoms in their farm workers or in him/herself (OR = 3.4; 95% CI: 1.3–8.7; p = 0.006) were more likely to be associated with Brucella infected herds than control herds. This evidence can be used in strategic planning to protect both human and herd health. Full article

(This article belongs to the Special Issue Brucella Species and Brucella melitensis)

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17 pages, 526 KiB

Open AccessArticle

Knowledge of Brucellosis, Health-Seeking Behaviour, and Risk Factors for Brucella Infection amongst Workers on Cattle Farms in Gauteng, South Africa

by Krpasha Govindasamy, Eric M. C. Etter, Bernice N. Harris, Jennifer Rossouw, Darrell A. Abernethy and Peter N. Thompson

Pathogens 2021, 10(11), 1484; https://doi.org/10.3390/pathogens10111484 - 14 Nov 2021

Cited by 4 | Viewed by 4231

Abstract

Brucellosis in humans is under-detected and underreported in sub-Saharan Africa. Risk factors associated with Brucella infection and health seeking behaviour in response to brucellosis-like symptoms, amongst cattle farm workers and veterinary officials in South Africa, are unknown. Farm workers and veterinary officials ( [...] Read more.

Brucellosis in humans is under-detected and underreported in sub-Saharan Africa. Risk factors associated with Brucella infection and health seeking behaviour in response to brucellosis-like symptoms, amongst cattle farm workers and veterinary officials in South Africa, are unknown. Farm workers and veterinary officials (N = 230) were screened for brucellosis using commercial Rose Bengal Test (RBT^®), IgM Enzyme-linked Immunoassay (ELISA)^®, IgG ELISA^® and the BrucellaCapt^® test. Knowledge of brucellosis and risk factors for exposure to Brucella were also investigated. Seroprevalence varied according to test used: 10.1% (RBT^®), 20.9% (IgG ELISA^®) and 6.5% (BrucellaCapt^®). Only 22.2% (6/27) of veterinary officials opt to visit a clinic, doctor, or hospital in response to self-experienced brucellosis-like symptoms, compared to 74.9% (152/203) of farm workers (p < 0.001). Of the BrucellaCapt^® seropositive participants, 53% (7/15) did not visit a clinic in response to brucellosis-like symptoms. Weak evidence of an association between the handling of afterbirth or placenta and infection of a short evolution (RBT^®, IgM ELISA^® and IgG ELISA^® seropositive) was found (OR = 8.9, 95% CI: 1.0–81.1, p = 0.052), and strong evidence of an association between this outcome and the slaughter of cattle (OR = 5.3, 95% CI: 1.4–19.6, p = 0.013). There was strong evidence of a positive association between inactive/resolved infection and veterinary officials vs. farm workers exposed to seropositive herds (OR = 7.0, 95% CI: 2.4–20.2, p < 0.001), with a simultaneous negative association with the handling of afterbirth or placenta (OR = 3.9, 95% CI: 1.3–11.3, p = 0.012). Findings suggest a proportion of undetected clinical cases of brucellosis amongst workers on cattle farms in Gauteng. Full article

(This article belongs to the Special Issue Brucella Species and Brucella melitensis)

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10 pages, 1785 KiB

Open AccessArticle

Serosurvey and Risk Factors Associated with Brucella Infection in High Risk Occupations from District Lahore and Kasur of Punjab, Pakistan

by Shahzad Ali, Usama Saeed, Muhammad Rizwan, Laiba Hassan, Muhammad Ali Syed, Falk Melzer, Hosny El-Adawy and Heinrich Neubauer

Pathogens 2021, 10(5), 620; https://doi.org/10.3390/pathogens10050620 - 18 May 2021

Cited by 6 | Viewed by 3320

Abstract

Brucellosis is a neglected zoonotic disease, and occupations with a high risk of infection exist. Limited information is available on brucellosis for these employees at high risk in Pakistan. A total of 459 persons with high-risk occupations, i.e., 211 abattoir workers, 63 milkers, [...] Read more.

Brucellosis is a neglected zoonotic disease, and occupations with a high risk of infection exist. Limited information is available on brucellosis for these employees at high risk in Pakistan. A total of 459 persons with high-risk occupations, i.e., 211 abattoir workers, 63 milkers, 52 dung cake makers, 44 veterinarians, 44 shepherds, and 45 veterinary students of the districts Kasur and Lahore, Pakistan, were tested in this study. Blood samples and information on place of residence, gender, age, urbanicity, type of occupation, socioeconomic status, contact with animals, consumption of raw milk, contact to women who had a miscarriage, contact to aborted animal fetus or abortion material, pregnancy, miscarriage history, or intrauterine fetal death were collected. Serum samples were examined using Rose Bengal tests for anti-Brucella antibodies and seropositive samples were subjected to genus-specific qPCR for the detection of DNA. Data were analyzed using chi-squared and binary regression. Twenty (4.35%) persons were seropositive for anti-Brucella antibodies. Out of these, 18 (90%) were tested positive by Brucella genus-specific qPCR. Positive sera were more often found in Lahore district (8.3%) than in Kasur district (3.1%). Persons older than 36 years were more often seropositive. Persons involved in the handing of milk and in contact with animals were more often seropositive. Contact with women who had had a miscarriage was also a significant factor for seropositivity for brucellosis. Place of residence, gender, age, urbanicity, and contact with animals were identified as potential risk factors in the present study. The present study confirmed that brucellosis is an occupation hazard for abattoir workers, milkers, dung cake makers, and veterinarians in the districts of Lahore and Kasur of Punjab, Pakistan. The study shows the need for strategies for safety at work to minimize the risk of infection. Raising awareness for the prevention and use of proper personal protection equipment during the slaughtering and treatment of animal is highly needed. Full article

(This article belongs to the Special Issue Brucella Species and Brucella melitensis)

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Review

Jump to: Research, Other

18 pages, 700 KiB

Open AccessReview

Pathogenicity and Its Implications in Taxonomy: The Brucella and Ochrobactrum Case

by Edgardo Moreno, José María Blasco, Jean Jacques Letesson, Jean Pierre Gorvel and Ignacio Moriyón

Pathogens 2022, 11(3), 377; https://doi.org/10.3390/pathogens11030377 - 21 Mar 2022

Cited by 27 | Viewed by 5200

Abstract

The intracellular pathogens of the genus Brucella are phylogenetically close to Ochrobactrum, a diverse group of free-living bacteria with a few species occasionally infecting medically compromised patients. A group of taxonomists recently included all Ochrobactrum organisms in the genus Brucella based on [...] Read more.

The intracellular pathogens of the genus Brucella are phylogenetically close to Ochrobactrum, a diverse group of free-living bacteria with a few species occasionally infecting medically compromised patients. A group of taxonomists recently included all Ochrobactrum organisms in the genus Brucella based on global genome analyses and alleged equivalences with genera such as Mycobacterium. Here, we demonstrate that such equivalencies are incorrect because they overlook the complexities of pathogenicity. By summarizing Brucella and Ochrobactrum divergences in lifestyle, structure, physiology, population, closed versus open pangenomes, genomic traits, and pathogenicity, we show that when they are adequately understood, they are highly relevant in taxonomy and not unidimensional quantitative characters. Thus, the Ochrobactrum and Brucella differences are not limited to their assignments to different “risk-groups”, a biologically (and hence, taxonomically) oversimplified description that, moreover, does not support ignoring the nomen periculosum rule, as proposed. Since the epidemiology, prophylaxis, diagnosis, and treatment are thoroughly unrelated, merging free-living Ochrobactrum organisms with highly pathogenic Brucella organisms brings evident risks for veterinarians, medical doctors, and public health authorities who confront brucellosis, a significant zoonosis worldwide. Therefore, from taxonomical and practical standpoints, the Brucella and Ochrobactrum genera must be maintained apart. Consequently, we urge researchers, culture collections, and databases to keep their canonical nomenclature. Full article

(This article belongs to the Special Issue Brucella Species and Brucella melitensis)

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14 pages, 1351 KiB

Open AccessReview

Microbiological Laboratory Diagnosis of Human Brucellosis: An Overview

by Giovanni Di Bonaventura, Silvia Angeletti, Andrea Ianni, Tommasangelo Petitti and Giovanni Gherardi

Pathogens 2021, 10(12), 1623; https://doi.org/10.3390/pathogens10121623 - 14 Dec 2021

Cited by 53 | Viewed by 11026

Abstract

Brucella spp. are Gram-negative, non-motile, non-spore-forming, slow-growing, facultative intracellular bacteria causing brucellosis. Brucellosis is an endemic of specific geographic areas and, although underreported, represents the most common zoonotic infection, with an annual global incidence of 500,000 cases among humans. Humans represent an occasional [...] Read more.

Brucella spp. are Gram-negative, non-motile, non-spore-forming, slow-growing, facultative intracellular bacteria causing brucellosis. Brucellosis is an endemic of specific geographic areas and, although underreported, represents the most common zoonotic infection, with an annual global incidence of 500,000 cases among humans. Humans represent an occasional host where the infection is mainly caused by B. melitensis, which is the most virulent; B. abortus; B. suis; and B. canis. A microbiological analysis is crucial to identifying human cases because clinical symptoms of human brucellosis are variable and aspecific. The laboratory diagnosis is based on three different microbiological approaches: (i) direct diagnosis by culture, (ii) indirect diagnosis by serological tests, and (iii) direct rapid diagnosis by molecular PCR-based methods. Despite the established experience with serological tests and highly sensitive nucleic acid amplification tests (NAATs), a culture is still considered the “gold standard” in the laboratory diagnosis of brucellosis due to its clinical and epidemiological relevance. Moreover, the automated BC systems now available have increased the sensitivity of BCs and shortened the time to detection of Brucella species. The main limitations of serological tests are the lack of common interpretative criteria, the suboptimal specificity due to interspecies cross-reactivity, and the low sensitivity during the early stage of disease. Despite that, serological tests remain the main diagnostic tool, especially in endemic areas because they are inexpensive, user friendly, and have high negative predictive value. Promising serological tests based on new synthetic antigens have been recently developed together with novel point-of-care tests without the need for dedicated equipment and expertise. NAATs are rapid tests that can help diagnose brucellosis in a few hours with high sensitivity and specificity. Nevertheless, the interpretation of NAAT-positive results requires attention because it may not necessarily indicate an active infection but rather a low bacterial inoculum, DNA from dead bacteria, or a patient that has recovered. Refined NAATs should be developed, and their performances should be compared with those of commercial and home-made molecular tests before being commercialized for the diagnosis of brucellosis. Here, we review and report the most common and updated microbiological diagnostic methods currently available for the laboratory diagnosis of brucellosis. Full article

(This article belongs to the Special Issue Brucella Species and Brucella melitensis)

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Other

Jump to: Research, Review

4 pages, 220 KiB

Open AccessBrief Report

Detection of Brucella abortus Vaccine Strain RB51 in Water Buffalo (Bubalus bubalis) Milk

by Daniela Averaimo, Fabrizio De Massis, Giovanni Savini, Giuliano Garofolo, Flavio Sacchini, Anna Abass, Manuela Tittarelli, Giacomo Migliorati and Antonio Petrini

Pathogens 2022, 11(7), 748; https://doi.org/10.3390/pathogens11070748 - 30 Jun 2022

Cited by 5 | Viewed by 1693

Abstract

The isolation of B. abortus RB51 vaccine strain from a milk sample in a water buffalo farm in southern Italy emphasizes the risk to public health of consuming contaminated milk or milk products following illegal vaccination. Full article

(This article belongs to the Special Issue Brucella Species and Brucella melitensis)

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