Understanding the relative risks of zoonosis emergence under contrasting approaches to meeting livestock product demand

Abstract

It has been argued that intensive livestock farming increases the risk of pandemics of zoonotic origin because of long-distance livestock movements, high livestock densities, poor animal health and welfare, low disease resistance and low genetic diversity. However, data on many of these factors are limited, and analyses to date typically ignore how land use affects emerging infectious disease (EID) risks, and how these risks might vary across systems with different yields (production per unit area). Extensive, lower yielding practices typically involve larger livestock populations, poorer biosecurity, more workers and more area under farming, resulting in different, but not necessarily lower, EID risks than higher yielding systems producing the same amount of food. To move this discussion forward, we review the evidence for each of the factors that potentially link livestock production practices to EID risk. We explore how each factor might vary with yield and consider how overall risks might differ across a mix of production systems chosen to reflect in broad terms the current livestock sector at a global level and in hypothetical low- and high-yield systems matched by overall level of production. We identify significant knowledge gaps for all potential risk factors and argue these shortfalls in understanding mean we cannot currently determine whether lower or higher yielding systems would better limit the risk of future pandemics.

The emergence and diversification of a zoonotic pathogen from within the microbiota of intensively farmed pigs

“…Studies of the impact of agricultural intensification on the risk of pathogen emergence generally focus on the most typical route: a pathogen jumping from one host species to another (4, 7, 35). In this study we instead described the emergence of an important zoonotic pathogen from within a largely commensal member of the respiratory microbiota of pigs.…”

“…While pathogen emergence typically arises through a pathogen jumping into a new host, pathogens can also emerge from within the microbiota already associated with a host population (5, 6). This route to pathogen emergence may be particularly important in intensive farming systems, where large population size and high population density may select for traits associated with pathogenicity while biosecurity reduces the risk of novel pathogens entering the population (7, 8).…”

Monkeypox: A Global Public Health Emergency of 2022- Are We Ready?

“…And 99% of the cases were males in the 31-43 years age group and, a significant portion of them being homosexual and bisexual. 6,7,8 Monkeypox is closely related to smallpox. According to WHO (World Health Organization), the smallpox vaccine is 85% cross-protective against monkeypox.…”

“…Afterwards, small outbreaks have been reported from other non-endemic areas of the world from time to time (Figure 2). 7,8 The disease then was prevalent among people not immunized against smallpox. 16 The recent outbreak began with the detection of a case in the UK on 6th May 2022 and then the subsequent cases in other parts of Europe were reported.…”

“…29,32 Some indicated persons, for example, health workers at high risk of exposure, laboratory personnel working with orthopoxviruses, clinical laboratory personnel performing laboratory testing for monkeypox, outbreak response team members, and other individuals who may be at high risk like persons with multiple sex partners can take vaccine for pre-exposure prophylaxis. 8,33 Historically, since monkeypox is a zoonotic disease, not only during outbreaks but also during normal periods, avoiding contact with risky animals and careful handling and cooking for the consumption of meat is especially important. In the case of imported rodents and nonhuman primates, suspected infected animals and other animals that have come in their contact should be handled with standard precautions, quarantined for 30 days, and observed for monkeypox symptoms.…”