Investigating the temporal and spatial distribution of foot‐and‐mouth disease virus serotype C in the Region of South America, 1968‐2016.

Abstract

Summary This study investigates the historical temporal trend and geographical distribution of the foot‐and‐mouth disease virus (FMDv) serotype C in South America; discussing the findings within the context of the actions and strategies carried out for the elimination of foot‐and‐mouth disease (FMD). This is the first time that such a comprehensive historical compilation has been carried out in the Region; hence, the study is intended as a reference and source of evidence about the presence/absence of FMDv serotype C in South America. Data on the occurrence of FMD were sourced from the Weekly Epidemiological Reports submitted by the countries to Pan American Foot‐and‐Mouth Disease Center (PANAFTOSA‐PAHO/WHO) since 1972, and complemented with other sources of information from the 1968–1971 period. The temporal distribution was examined with local weighted regression (LOESS) to identify two temporal trends, that is, “smoothed” and “over‐adjusted”, utilising the time‐series with the total number of cases per year, at Regional level. Thereafter the outbreaks were aggregated by decades and mapped by the first subnational administrative level. As a result, two major peaks of occurrence were identified, one in the 70s, with up to 1,193 outbreaks, and another in the 80s, with 380. Overall, the investigations show a clear regressive trend in the occurrence of serotype C, with a reduction in the number of outbreaks over‐time, and with the subsequent reduction of affected locations. This study illustrates the contrast between the very limited presence over the last 20 years – with only one event in 2004 – and the epidemic situation in the 1970s and 1980s, and suggests that serotype C of FMDv is no longer present in the Region.

A scoping review of foot‐and‐mouth disease risk, based on spatial and spatio‐temporal analysis of outbreaks in endemic settings

“…A total of 51 studies were included through the combined electronic and manual search strategy after an initial pool of over 500 publications that were screened; 88 reports were assessed in full text and of those, 37 were excluded because they did not fulfil the eligibility criteria (Figure 2 ). Among the included studies, three documented national or regional paths towards FMDv control and WOAH recognition as an FMD‐free territory based on the analysis of retrospective case series of FMD outbreaks (Abdrakhmanov et al., 2018 ; Gallego et al., 2007 ; Sanchez‐Vazquez et al., 2019 ). All the characteristics of included studies are summarized in Table S5 .…”

“…Conventional GLM or GLMM Poisson (Arjkumpa et al., 2020 ; Kerfua et al., 2018 ), negative binomial (Gunasekera et al., 2017 ), linear (Aman et al., 2020 ; Gallego et al., 2007 ; Jemberu et al., 2016 ; Perez et al., 2011 ; Woldemariyam et al., 2022 ) or logistic regression (Jemberu et al., 2016 ) models were used to explore or test hypothesis related to temporal trends. Other studies resorted to Bayesian approaches (Branscum et al., 2008 ; Choi et al., 2012 ; Gunasekera et al., 2022 ; Richards et al., 2014 ), additive models (Aman et al., 2020 ), spectral analysis (Perez et al., 2011 ), locally weighted regression (Sanchez‐Vazquez et al., 2019 ), normalized temporal trends (Madin, 2011 ), time series (Gallego et al., 2007 ), regression tree models (Souley Kouato et al., 2018 ) and models fitted to inverted correlograms (Gilbert et al., 2005 ) to analyse temporal data. Moreover, 13 studies formally analysed FMD seasonality through the calculation of seasonal indexes (Abdrakhmanov et al., 2018 ; Gallego et al., 2007 ; Perez et al., 2011 ), seasonal decomposition (Madin, 2011 ; Woldemariyam et al., 2022 ), randomness tests (Aman et al., 2020 ; Gallego et al., 2007 ; Jemberu et al., 2016 ) or by fitting frequentist or Bayesian models to temporal data (Choi et al., 2012 ; Guerrini et al., 2019 ; Jafarzadeh et al., 2014 ; Kerfua et al., 2018 ; Rahman et al., 2020 ).…”

Advances in the eradication of foot-and-mouth disease in South America: 2011–2020

“…The occurrence of FMD caused by the type C virus in South America was described by Saraiva and López ( 30 ), and more recently by Sanchez-Vazquez et al ( 31 ), while its phylogenetic evolution in the subcontinent was described by Paton et al ( 32 ). In 2016, 12 years after the last case of FMD caused by the type C virus, only four countries in South America (Argentina, Bolivia, Brazil, and Paraguay) kept the type C virus in their vaccines in use.…”

Optimization of a foot-and-mouth disease virus Southern African Territories–specific solid-phase competitive ELISA for small ruminant serum samples

“…11 Serotype C was last reported in 2004. 28,31,32 The SAT serotypes are mainly restricted to sub-Saharan Africa, although incursions into the Middle East, North Africa, and Greece have been reported. 1,19 The most common clinical signs of FMD are pyrexia, lameness, drooling, and vesiculation.…”