Building the Evidence Base for the Prevention of Raw Milk-Acquired Brucellosis: A Systematic Review

Human Brucellosis in the Rural and Urban Population of Pakistan: Seroprevalence, Risk Factors, and Clinical Manifestations

Brucella spp. is the bacterium responsible for brucellosis, a zoonotic infection that affects humans. This disease poses significant health challenges and contributes to poverty, particularly in developing countries. This study aimed to assess the seroprevalence, risk factors, and clinical symptoms of human brucellosis within the general population of Multan and Muzaffargarh, Pakistan. A total of 307 blood samples were collected from patients visiting local hospitals in Multan and Muzaffargarh between August 2015 and January 2016. Demographic information, risk factors, and clinical outcomes were documented. Serum samples were initially screened for anti-Brucella antibodies using the Rose Bengal Plate Test, and positive cases were subsequently confirmed through RT-PCR. The chi-square test assessed the link between Brucella positivity and the identified risk factors. The study recorded an overall seroprevalence of 6.8%, with 8.9% in Multan and 4.3% in Muzaffargarh. Genus-specific Brucella detection through RT-PCR confirmed that 20 out of 21 samples were positive. Significant associations with human brucellosis were found for contact with aborted animals (p = 0.032) and consumption of raw milk (p = 0.031), while factors such as age, gender, occupation, urbanicity, and geographical region did not show a significant impact on seropositivity (p > 0.05). Non-specific clinical symptoms were commonly observed among seropositive patients. The findings highlight the significance of close human interaction with infected animals, especially concerning livestock practices and dairy product consumption. The results also emphasize the importance of focusing efforts on raising awareness in risky occupations and developing control programs by healthcare authorities.

Practical Steps to Design Brucellosis Preventive Interventions: An Intervention Mapping Approach

Background and Aims

Common diseases between humans and animals are one of the health problems of countries, which requires targeted intervention. The intervention mapping model provides guidance for choosing the most appropriate methods and applications. Since one of the most important challenges in the endemic areas of Iran is the control of brucellosis. Therefore, the aim of this research is to examine the intervention mapping model and its steps to design interventions to prevent this disease.

Methods

In this research, the practical steps of the Brucellosis prevention intervention were carried out with the intervention mapping approach in six steps from July 2023 to December 2023. In the first step, needs assessment was done through literature review, semi-structured in-depth interview and checklist. In the second step, the matrix of change objectives was designed. After selecting intervention methods based on theory and practical applications, and producing program components and materials, the intervention was implemented and evaluated.

Results

Intervention mapping helped us in designing and implementing the brucellosis control educational program with the participation of participants, specifying the definition of results, performance goals and determinants, theoretical methods, practical applications, intervention design, implementation and step-by-step evaluation.

Conclusion

The intervention mapping approach ensures the transparency of all intervention components and it provides a useful approach for developing behavior change interventions.

Brucellosis outbreak in a remote village in northwestern Tajikistan in 2023: a matched case-control study

Background

A sharp increase in reported brucellosis incidence was observed in northwestern Tajikistan (from 1.0/100,000 people in January-May 2022 to 32.7/100,000 in January-May 2023). Most (82%) cases were from the same remote mountainous village (population = 10,712). The aim of this study was to identify risk factors for brucellosis infection and mitigate disease risk.

Methods

Using a case-control design, we conducted face-to-face interviews and collected blood samples during May-June 2023. Fifty-seven cases and 114 controls were recruited. Cases were the first person in a household diagnosed with brucellosis during February-June 2023 with positive serum agglutination test and antibody titers ≥1/160 from blood samples. Two controls were selected for each case (neighbors from different households matched by age and sex). Controls testing positive were excluded and replaced. We conducted conditional multivariable logistic regression to calculate adjusted odds ratio (AOR) and 95% confidence intervals (CI).

Results

Among the 87 brucellosis patients reported, 57 (66%) agreed to participate and didn't have secondary cases in the household. Of the 57 cases, 68% were 15-44 years old, and 44% were male. Cases peaked in May 2023. Common symptoms were joint pain (95%), fever (84%), weakness (72%), and night sweats (65%). Of selected controls, 13% tested positive and were excluded. All cases and 94% of controls owned livestock (mostly cattle, sheep, or goats); no animals had not been vaccinated in the past 5 years. Brucellosis was associated with consumption of both homemade kaymak (clotted cream) and home-raised meat compared with neither (AOR: 59 [95%CI: 4.3-798], p < 0.01), home-raised meat but not kaymak compared with neither (AOR: 54 [4.0-731], p < 0.01), and involvement in animal slaughter compared with no involvement (AOR: 36 [2.8-461], p < 0.01).

Conclusion

Contact with unvaccinated livestock or consumption of their products was a key contributor to this outbreak in a remote village of Tajikistan. With 13% of controls testing positive, true incidence was likely greater than reported. Following our investigation, a brucellosis awareness education campaign and animal vaccination campaigns were carried out in the region and only one case was reported in September 2023.

Responding to outbreaks of illness linked to unpasteurized milk: A needs assessment of state health and agriculture departments

AIMS

Consumption of unpasteurized milk can result in severe illness or death. In the United States, the number of people who regularly consume unpasteurized milk is relatively low, but outbreaks resulting from unpasteurized milk outnumber outbreaks linked to pasteurized milk. The sale of unpasteurized milk for human consumption through interstate commerce is prohibited at the federal level, but laws among states vary considerably with respect to the sale of unpasteurized milk. Each state has a different perspective on responding to and preventing outbreaks of illness linked to consuming unpasteurized milk.

METHODS AND RESULTS

We conducted a needs assessment of state health and agriculture departments to gather information on state-level strategies to prevent illnesses linked to consuming unpasteurized milk, characterize challenges states face, and identify areas where partners can support state efforts to prevent illnesses. We deployed a survey from 6 January 2021 to 1 March 2021, using a snowball sampling strategy and had 158 respondents. Of 115 respondents, 46 (40%) believed that state laws were ineffective in preventing illnesses, and 92 (80%) agreed that consumers continue to find ways to get unpasteurized milk despite laws restricting sale. Respondents from 19 states were aware of future legislative or regulatory efforts surrounding unpasteurized milk in their state, with 14 (74%) indicating these efforts would expand consumer access. The most common outbreak prevention strategies respondents mentioned included sharing knowledge and experiences with other public health and agriculture officials, providing information to inform legislative efforts, and communicating to the public about outbreaks. Most respondents (41/50, 91%) were interested in pursuing further efforts to prevent unpasteurized milk-associated illnesses in their state.

CONCLUSIONS

The results from this needs assessment can be used to inform future strategies for preventing illness outbreaks associated with unpasteurized milk consumption.

Activation of mucosal immunity as a novel therapeutic strategy for combating brucellosis

Brucellosis is a disease of livestock that is commonly asymptomatic until an abortion occurs. Disease in humans results from contact of infected livestock or consumption of contaminated milk or meat. Brucella zoonosis is primarily caused by one of three species that infect livestock, Bacillus abortus in cattle, B. melitensis in goats and sheep, and B. suis in pigs. To aid in disease prophylaxis, livestock vaccines are available, but are only 70% effective; hence, improved vaccines are needed to mitigate disease, particularly in countries where disease remains pervasive. The absence of knowing which proteins confer complete protection limits development of subunit vaccines. Instead, efforts are focused on developing new and improved live, attenuated Brucella vaccines, since these mimic attributes of wild-type Brucella, and stimulate host immune, particularly T helper 1-type responses, required for protection. In considering their development, the new mutants must address Brucella's defense mechanisms normally active to circumvent host immune detection. Vaccination approaches should also consider mode and route of delivery since disease transmission among livestock and humans is believed to occur via the naso-oropharyngeal tissues. By arming the host's mucosal immune defenses with resident memory T cells (TRMs) and by expanding the sources of IFN-γ, brucellae dissemination from the site of infection to systemic tissues can be prevented. In this review, points of discussion focus on understanding the various immune mechanisms involved in disease progression and which immune players are important in fighting disease.