Biology subjects

Mazeri, S.

Publications and source records attributed to Mazeri, S..

7 recordsLinked to original sources

bioRxiv2026

Modelling sterilisation strategies to maximise population impact and cost-efficiency in free-roaming dog populations

Free-roaming dog populations pose challenges to public health and animal welfare, and their management and protection is legally mandated in many countries to control zoonotic diseases such as rabies, reduce bites, mitigate fear of aggressive dogs, and preserve animal welfare. Although international organisations recommend holistic dog population management with surgical sterilisation as a key component, stakeholders report a lack of evidence-based guidance on effective and cost-efficient strategies. To address this, we developed a deterministic model of a closed free-roaming dog (FRD) population, including dogs dependent on and independent of humans, parameterised using data from southern India. We evaluated a wide range of sterilisation strategies varying duration, interval, frequency, intensity, targeting different population subsets, and fixed or responsive approaches. Strategies were assessed based on their effects on independent FRD population size and implementation costs. Female sterilisation coverage (FSC) strongly determined population reduction and cost-effectiveness. Repeated, short sterilisation periods with appropriately timed intervals and high early intensity best balanced population reduction and cost-efficiency. Excluding dependent dogs (cared for by humans) severely constrained population reduction, while male sterilisation enhanced impact at little extra cost, assuming direct effects on pregnancy rates. Costs and population impacts can be visualised on an interactive web application (https://field.shinyapps.io/DogPopSimApp), allowing practitioners and policymakers to explore sterilisation strategy outcomes. Overall, cost-effective population reduction required sustained commitment and coverage-driven strategies that balance welfare, population reduction and the operational needs of dog-mediated rabies control. Author SummaryFree-roaming street dogs live closely with people. While these animals are often valued members of the community, they can raise public health and safety concerns, including disease transmission, bites, and traffic accidents. To protect both human and animal health, many regions use surgical sterilisation to humanely manage street dog populations. However, running these programmes is complex and expensive, and community managers often lack clear guidance on how to maximise their limited resources. To address this, we used data from southern India to create a mathematical model of a street dog population. We simulated thousands of different sterilisation strategies to see how factors like campaign length, frequency, and targeted sub-groups impacted population size and total costs. We found that short, repeated sterilisation campaigns offer the best balance of population reduction and cost-efficiency. Crucially, these programmes must include dogs that are partially cared for by humans; otherwise, their puppies will continually replenish the street population. Although sterilisation of females drives population reduction, sterilising males alongside females enhanced the overall impact. Ultimately, our study provides practical, evidence-based guidance to help communities design effective and financially sustainable dog management programmes that improve public health and animal welfare.

ecology↗

bioRxiv2023

Emergence and spread of feline infection peritonitis due to a highly pathogenic canine/feline recombinant coronavirus

Cross-species transmission of coronaviruses (CoVs) poses a serious threat to both animal and human health1-3. Whilst the large RNA genome of CoVs shows relatively low mutation rates, recombination within genera is frequently observed and demonstrated4-7. Companion animals are often overlooked in the transmission cycle of viral diseases; however, the close relationship of feline (FCoV) and canine CoV (CCoV) to human hCoV-229E5,8, as well as their susceptibility to SARS-CoV-29 highlight their importance in potential transmission cycles. Whilst recombination between CCoV and FCoV of a large fragment spanning orf1b to M has been previously described5,10, here we report the emergence of a novel, highly pathogenic FCoV-CCoV recombinant responsible for a rapidly spreading outbreak of feline infectious peritonitis (FIP), originating in Cyprus11. The minor recombinant region, spanning spike (S), shows 96.5% sequence identity to the pantropic canine coronavirus NA/09. Infection has rapidly spread, infecting cats of all ages. Development of FIP appears very frequent and sequence identities of samples from cats in different districts of the island is strongly supportive of direct transmission. A near cat-specific deletion in the domain 0 of S is present in >90% of FIP cats. It is unclear as yet whether this deletion is directly associated with disease development and may be linked to a biotype switch12. The domain 0 deletion and several amino acid changes in S, particularly the receptor binding domain, indicate potential changes to receptor binding and cell tropism.

microbiology↗

bioRxiv2021

Inferring livestock movement networks from archived data to support infectious disease control in developing countries

The use of network analysis to support livestock disease control in low middle-income countries (LMICs) has historically been hampered by the cost of generating empirical data in the absence of animal movement recording schemes. To fill this gap, methods which exploit freely available demographic and archived molecular data can be used to generate livestock networks based on gravity and phylogeographic modelling techniques, respectively. However, questions remain on the performance of these methods in capturing the topology of empirical networks. Here, we compare output from these network methodologies to a network constructed from either empirical data or randomly generated data. To facilitate this comparison, the spread of infectious diseases was simulated, it is this evaluation that demonstrates their potential utility to inform robust livestock disease control strategies. The molecular network was the closest approximation to the empirical network, both in relation to topological and epidemic characteristics, whereas size of epidemics in the gravity network tended to be larger, better agreement across all three networks was observed when; a) total nodes infected, b) percentage infection take off were compared. These methods consistently identified the same important animal movement and trade hotspots as the empirical networks. We therefore consider this proof-of-concept that demographic data such as censuses and archived molecular data could be repurposed to inform livestock disease management in LMICs. Author summaryLive animal movements in Africa represent a significant risk of transmission and spread of infectious diseases in livestock populations, and therefore, have direct implications on the food security of the continent. Here we explore the potential utility of available data to support control strategies, by comparing movement networks inferred from such data i.e. census and pathogen molecular data using gravity modelling and phylogeography respectively. Their utility is evaluated by comparing their topology and disease spread characteristics to empirical live animal movement. Based on our results, we posit that archived data can be repurposed to support infectious disease control on the African continent.

scientific communication and education↗

bioRxiv2020

Baseline epidemiology and associated dog ecology study towards stepwise elimination of rabies in Kwara state, Nigeria

Understanding domestic dog population dynamics and ecology is necessary for any effective rabies control program. This study was conducted as part of the baseline epidemiological studies necessary for the establishment of the Kwara Rabies Rapid Alert System "KRRAS". The aim of this study was to determine the dog population structure of Kwara State by assessing the dog ownership, vaccination status, and prevalence of dog bites. A total of 1,460 questionnaires were administered to respondents in the three senatorial zones of the state using Open Data Kit (ODK) between June 2019 to January 2020. Of the 1460 households surveyed, 293 (20.1%) owned at least one dog with an average of 2.25 dogs per household. The male to female ratio was 2.2:1 and 85% (n=250/293) of the owned dogs were local breeds. A total of 785 dogs was enumerated (659 dogs from 293 households and 126 free-roaming dogs) and 7811 persons which resulted in a dog-human ratio of 1:9.95. The estimated dog population is 376,789 (95% CI: 343,700 - 379,878). The dog anti-rabies vaccination coverage was 31% (n=92/293). The prevalence of dog-bite was 13% (n=193/1460) of which only 27% of the victims (n=61/225) received post-exposure prophylaxis (PEP). The ethnicity of respondents had a significant impact on dog ownership. Yorubas more often (OR: 2.2-5; 95% CI: 1.2 - 12.4; p < 0.001) owned dogs than other tribes. The vaccination status of owned dogs was greatly impacted by the level of education of the respondents (OR: 5.03; 95% CI: 1.5073 - 16.8324; p < 0.001); the breed of the dog with exotic dogs being more vaccinated (OR: 2.8; 95% CI: 0.7150 - 10.857; p < 0.001) and the confinement of the dog (OR: 2.07; 95% CI: 1.1592 - 3.7037; p < 0.001). Always confined dogs were twice more vaccinated than non-confined dogs. The results of the study showed that the vaccination coverage needs to be increased, the number of dog bites needs to be reduced, the number of non-confined dogs needs to be reduced and stray dog control strategies need to be implemented. The findings of this study showed very low vaccination coverage for dogs which is below the 70-80% target recommended for herd immunity by the world health organization.

microbiology↗

bioRxiv2020

A putative genomic map for resistance of Bos indicus cattle in Cameroon to bovine tuberculosis

Bovine Tuberculosis (bTB) caused by Mycobacterium bovis is a livestock disease of global economic and public health importance. There are currently no effective vaccines available for livestock and so control relies on animal level surveillance and pasteurisation of dairy products. A new alternative control approach is to exploit the genetic variability of the host; recent studies have demonstrated that breeding Bos taurus cattle for increased resistance to bTB is feasible. The utility of such an approach is still unknown for the Bos indicus cattle population. This study aims to assess genetic variation in bTB resistance and the underlying genomic architecture in Bos indicus breeds in Cameroon. We conducted a cross-sectional study of slaughter cattle in Cameroon and genotyped a sample of 213 cattle. Their genomic diversity was characterised using PCA, hierarchical clustering and admixture analysis. We assessed genetic variation in bTB resistance using heritability analysis and compared quantitative trait loci. Previous studies had found that breed was an important factor in explaining the epidemiology of bTB, with Fulani cattle appearing to be more susceptible than mixed breeds. However, we show that the apparent phenotypic differences in visual appearance between the breeds was not reflected by clear genomic differences. At the genetic level, cattle belonging to different hierarchical genomic clusters differed in their susceptibility to bTB. There was evidence of a genomic association between M. bovis infection status with specific SNPs. We highlight the need to understand the challenges faced by livestock in specific settings both in terms of pathogens and the environment, in addition to their intended purpose and how they fit into a defined management system. It is only at this point livestock keepers can then make informed breeding choices, not only for resistance to disease but also for increasing production.

genetics↗

bioRxiv2019

The evolution and phylodynamics of serotype A and SAT2 foot-and-mouth disease viruses in endemic regions of Africa

Foot-and-mouth disease (FMD) is a major livestock disease with direct clinical impacts as well as indirect trade implications. Control through vaccination and stamping-out has successfully reduced or eradicated the disease from Europe and large parts of South America. However, sub-Saharan Africa remains endemically affected with 5/7 serotypes currently known to be circulating across the continent. This has significant implications both locally for livestock production and poverty reduction but also globally as it represents a major reservoir of viruses, which could spark new epidemics in disease free countries or vaccination zones. This paper describes the phylodynamics of serotypes A and SAT2 in Africa including recent isolates from Cameroon in Central Africa. We estimated the most recent common ancestor for serotype A was an East African virus from the 1930s compared to SAT2 which has a much older common ancestor from the early 1700s. Detailed analysis of the different clades shows clearly that different clades are evolving and diffusing across the landscape at different rates with both serotypes having a particularly recent clade that is evolving and spreading more rapidly than other clades within their serotype. However, the lack of detailed sequence data available for Africa seriously limits our understanding of FMD epidemiology across the continent. A comprehensive view of the evolutionary history and dynamics of FMD viruses is essential to understand many basic epidemiological aspects of FMD in Africa such as the scale of persistence and the role of wildlife and thus the opportunities and scale at which vaccination and other controls could be applied. Finally we ask endemic countries to join the OIE/FAO supported regional networks and take advantage of new cheap technologies being rolled out to collect isolates and submit them to the World Reference Laboratory.

epidemiology↗

bioRxiv2019

A high throughput deep amplicon sequencing method to show the emergence and spread of Calicophoron daubneyi in United Kingdom cattle herds.

The prevalence of C. daubneyi infection in the United Kingdom has increased, but despite the potential for rumen flukes to cause production loss in ruminant livestock, understanding of their emergence and spread is poor. Here we describe the development of a method to explore the multiplicity of C. daubneyi infection and patterns of the parasites emergence and spread, based on Illumina MiSeq deep sequencing of meta barcoded amplicons of a fragment of the mt-COX-1 locus. Our results show high levels of genetic diversity per infection and between populations of 10 to 47 of adult C. daubneyi, each from a total of 32 finished prime cattle consigned to slaughter from northern United Kingdom; with 18 unique mt-COX-1 haplotypes. This has implications for the adaptability of environmental and intermediate host stages of the parasite to changing climatic and animal management conditions, or of parasitic stages to exposure to anthelmintic drugs; potentially allowing for greater pathogenicity, or the development of anthelmintic resistance, respectively. Our results illustrate the impact of high levels of animal movements in the United Kingdom, whereby multiple common mt-COX-1 haplotypes were identified in 26 populations in the absence of geographical clustering of clades.

evolutionary biology↗