Environmental persistence of foot‐and‐mouth disease virus applied to endemic regions

Abstract

The consequences of foot‐and‐mouth disease impact regional economies and food security through animal mortality and morbidity, trade restrictions and burdens to veterinary infrastructure. Despite efforts to control the disease, some regions, mostly in warmer climates, persistently report disease outbreaks. Consequently, it is necessary to understand how environmental factors influence transmission, of this economically devastating disease. Extensive research covers basic aetiology and transmission potential of livestock and livestock products for foot‐and‐mouth disease virus (FMDV), with a subset evaluating environmental survival. However, this subset, completed in the early to mid‐20th century in Northern Europe and the United States, is not easily generalized to today's endemic locations. This review uncovered 20 studies, to assess current knowledge and analyse the effects of environmental variables on FMDV survival, using a Cox proportional hazards (Coxph) model. However, the dataset is limited, for example pH was included in three studies and only five studies reported both relative humidity (RH) and temperature. After dropping pH from the analysis, our results suggest that temperature alone does not describe FMDV survival; instead, interactions between RH and temperature have broader impacts across various conditions. For instance, FMDV is expected to survive longer during the wet season (survival at day 50 is ~90% at 16°C and 86% RH) versus the dry season (survival at day 50 approaches 0% at 16°C and 37.5% RH) or comparatively in the UK versus the Southwestern United States. Additionally, survival on vegetation topped 70% on day 75 when conditions exceeded 20°C with high RH (86%), drastically higher than the survival on inanimate surfaces at the same temperature and RH (~0%). This is important in tropical regions, where high temperatures can persist throughout the year, but RH varies. Therefore, parameter estimates, for disease modelling and control in endemic areas, require environmental survival data from a wider range of conditions.

Foot-and-Mouth Disease Space-Time Clusters and Risk Factors in Cattle and Buffalo in Bangladesh

“…A similar findingbased on descriptive analysis onlywas reported by another retrospective epidemiologic study in Bangladesh [15]. The average temperature (23.5 °C) and relative humidity (RH) (66%) in November are favorable for the survival of FMDV, which might be a reason for the higher prevalence of FMD [19]. Chattogram division shares a common boundary with India and Myanmar.…”

“…The survival of FMDV is dependent on various climatic and microclimatic conditions. The optimal conditions for FMDV survival in the environment are <20 ℃ temperature and >55% relative humidity (RH) [ 19 ]. Temperature <20 ℃ only occurs in the winter season in Bangladesh.…”

“…The average temperature in the pre-monsoon season in Bangladesh is 27.4 ℃ (relatively high) but the RH is 57.3% (favorable). As temperatures increase, desiccation reduces viral survival; however, high RH will reduce the potential for desiccation and increase the survival rate of virus [ 19 ]. It was also reported from one study that the prevalence of FMD is significantly higher in sub-humid than semi-arid zones [ 23 ].…”

Seasonal dynamics of the wild rodent faecal virome

“…For example, hepatitis A virus (genus Hepatovirus , family Picornavidae ) is very stable under a broad range of temperature, humidity, and pH conditions and can survive over three months in the environment (Sobsey et al, 1988). In contrast, other picornaviruses, such as Foot and Mouth disease virus (genus Aphthovirus) , appear to be less stable in the environment, with longer survival times observed at higher humidity and moderate temperatures (Abad et al, 1994; Mbithi et al, 1991; Mielke and Garabed, 2020). Although we observed clear seasonality in picornavirus detection and abundance, given the substantial temporal turnover in viral diversity, it is reasonable to assume that other viruses in Wytham rodents also circulated seasonally, especially those detected transiently in the population (e.g., Coronavirus, Paramyxovirus ).…”

Assessing epidemiological parameters and dissemination characteristics of the 2000 and 2001 foot-and-mouth disease outbreaks in Rio Grande do Sul, Brazil

“…Direct contact between infected and susceptible animals is the main transmission route because the FMD virus is often present in the body fluids of acutely infected animals and aerosol shedding. The indirect exposure to the excretions and secretions of acutely infected animals or uncooked meat products may be a source of infection to susceptible animals (Colenutt et al, 2020;Mielke & Garabed, 2020;Paton et al, 2018;Rueda et al, 2015). FMD control and eradication are challenging and expensive, mainly because of international trade bans and the direct and indirect costs of control and eradication activities (Junker et al, 2009;Kitching & Alexandersen, 2002;Pendell et al, 2007).…”