The witchweed Striga gesnerioides and the cultivated cowpea: A geographical and historical analysis of their West African distribution points to the prevalence of agro-ecological factors and the parasite’s multilocal evolution potential

The increasing severity of Striga gesnerioides attacks on cowpea across West Africa has been related to its prolificity, seed mobility and longevity, and adaptation to aridity, in a context of agricultural intensification. To understand this fast extension, we analyzed (1) the distributions of the crop and the witchweed with ecological niche modeling and multivariate climate analysis, and (2) the chronological information available from collections and the literature. The ecoclimatic envelope of S. gesnerioides attacks on cowpea is the same as on wild hosts. Consistently, the modeled distribution of cowpea infestations is closely similar to the simple superposition of the parasite model (involving all hosts) and the crop model. Striga gesnerioides infestations are restricted to the driest component of the cultivated cowpea ecoclimatic niche, corresponding to the Sahelian and Sudano-Sahelian belts and the Dahomey gap. Thus, the parasite distribution, determined by its own requirements, does not constrain cowpea cultivation under Guinean climates. The spatial and temporal distributions of S. gesnerioides field infestations are consistent with an earlier impact on cowpea production in eastern West Africa, related itself to a similar trend in cowpea cultivation intensification from Niger, Nigeria and Benin to Burkina Faso and Ghana. Mali and Senegal were affected later, and literature reports of Senegalese strains of S. gesnerioides from the wild developing virulence on cowpea offer a model for the diffusion of witchweed parasitism by multilocal evolution, through host-driven selection, instead of epidemic diffusion. A contrario, in Côte d’Ivoire, cowpea is much less widespread, so the parasite has remained confined to the wild compartment. Thus, both historical and ecogeographic analyses refute the vision of S. gesnerioides as an invader. Instead, they point to the increasing importance and intensification of the crop, and the consequent loss of biodiversity, as the main drivers of the extension and diversification of its crop-specific strains.

The Eurasian strawberry blossom weevil, Anthonomus rubi (Herbst, 1795), is established in North America

We report the strawberry blossom weevil, Anthonomus rubi (Herbst, 1795) (Coleoptera: Curculionidae), a species native to Europe, Asia, and North Africa, as established in British Columbia, Canada. This is the first report of A. rubi in North America. We provide a diagnosis of the species and compare it with other species of the genus Anthonomus Germar in Canada. This species is a pest of plants in Rosaceae Jussieu, including economically important berries such as strawberries (Fragaria Linnaeus) and raspberries (Rubus idaeus Linnaeus), and of native berries of importance to Indigenous peoples in Canada. Female weevils oviposit eggs inside developing flower buds and sever flower stalks, facilitating larval development inside damaged buds and thus reducing fruit yields. Surveys to confirm the presence of A. rubi conducted in 2020 found the weevil to be well established in cultivated and wild hosts throughout the Greater Vancouver area and Fraser Valley, British Columbia. At least one species of parasitoid wasp in the genus Pteromalus Swederus (Hymenoptera: Pteromalidae) has been found in association with A. rubi in the province. Future investigations are required to understand the biology of A. rubi in its new range, assess its impact on berries, and develop management strategies.

Toxoplasma gondii infections are associated with costly boldness toward felids in a wild host

Toxoplasma gondii is hypothesized to manipulate the behavior of warm-blooded hosts to promote trophic transmission into the parasite’s definitive feline hosts. A key prediction of this hypothesis is that T. gondii infections of non-feline hosts are associated with costly behavior toward T. gondii’s definitive hosts; however, this effect has not been documented in any of the parasite’s diverse wild hosts during naturally occurring interactions with felines. Here, three decades of field observations reveal that T. gondii-infected hyena cubs approach lions more closely than uninfected peers and have higher rates of lion mortality. We discuss these results in light of 1) the possibility that hyena boldness represents an extended phenotype of the parasite, and 2) alternative scenarios in which T. gondii has not undergone selection to manipulate behavior in host hyenas. Both cases remain plausible and have important ramifications for T. gondii’s impacts on host behavior and fitness in the wild.

Spatial epidemiology of Leptospira sp. exposure in bovines from Veracruz, México

Bovine leptospirosis is a bacterial disease that affects cattle herds, causing economic losses due to reproductive problems, which require expensive treatments. The main source of transmission for cattle is still uncertain, but it has been described that rodents and bats can play an important role in the transmission cycle by being maintenance hosts for the pathogenic species of the bacterium and spreading it through urine. In this study, we characterize possible risk areas for bovine leptospirosis exposure in the state of Veracruz, Mexico, based on the geographical distribution of flying (bats) and terrestrial (rodents and opossums) wild hosts of Leptospira sp. reported in Mexico in addition with climatic, geographic, soil characteristics, land use and human activities variables (environmental variables). We used a generalized linear regression model (GLM) to understand the association between the frequency of anti- Leptospira sp. antibodies (a proxy of exposure to) in cattle herds exposed to Leptospira, the favorability of wild hosts of Leptospira as well as the environmental variables. The parameterized model explains 12.3% of the variance. The frequency of anti- Leptospira sp. antibodies exposoure in cattle herds was associated with elevation, geographic longitude, pH of the soil surface and environmental favorability for the presence of rodents, opossums, and bats. The variation in exposure is mainly explained by a longitudinal gradient (6.4% of the variance) and the favorability-based indices for wild hosts (9.6 % of the variance). Describing the possible risks for exposure to Leptospira in an important and neglected livestock geographical region, we provide valuable information to the selection of areas for diagnosis and prevention of this relevant disease.

Sesamia cretica (greater sugarcane borer).

The geographical range of S. cretica includes most of the countries and islands of the Mediterranean basin and extends through the Middle East and Arabia to Pakistan, northern India and northern Africa, extending south to northern Kenya and northern Cameroon. According to Tams and Bowden (1953) this species does not extend westward of Cameroon; however, earlier records from Mali, Niger and Togo have again been included on the recently revised CABI/EPPO (2001) distribution map. This is a pest species linked to graminaceous crops with a preference for sorghum, maize and sugarcane. It is present on wild Gramineae with a preference for Panicum repens. S. cretica could extend its range following these crops/wild hosts and in correlation with climatic change. More studies on the distribution of this species are necessary. It belongs to the 'Sesamia' group of noctuids, a group of very similar species that are difficult to identify, and therefore misidentifications can occur regarding new distribution data.

Molecular Typing of Pathogenic Leptospira Species Isolated from Wild Mammal Reservoirs in Sardinia

Leptospirosis is a global zoonosis caused by pathogenic species of Leptospira that infect a large spectrum of domestic and wild animals. This study is the first molecular identification, characterization, and phylogeny of Leptospira strains with veterinary and zoonotic impact in Sardinian wild hosts. All samples collected were cultured and analyzed by multiplex real time polymerase chain reaction (qPCR). Sequencing, phylogenetic analyses (based on rrs and secY sequences), and Multilocus Sequence Typing (MLST) based on the analysis of seven concatenated loci were also performed. Results revealed the detection of Leptospira DNA and cultured isolates in 21% and 4% of the samples examined, respectively. Sequence analysis of Leptospira positive samples highlighted the presence of the interrogans and borgpetersenii genospecies that grouped in strongly supported monophyletic clades. MLST analyses identified six different Sequence Types (ST) that clustered in two monophyletic groups specific for Leptospirainterrogans, and L. borgpetersenii. This study provided about the prevalence of leptospires in wild mammals in Sardinia, and increased our knowledge of this pathogen on the island. Monitoring Leptospira strains circulating in Sardinia will help clinicians and veterinarians develop strategic plans for the prevention and control of leptospiral infections.

Trioza erytreae (African citrus psyllid).

The invasive African psyllid, Trioza erytrea, transmits the causal agent of the African form of citrus huanglongbing (greening) disease, Liberibacter africanum, a very destructive disease of citrus plants. It does this under natural conditions in Africa and the Middle East, and has been shown experimentally to transmit the Asian form, Liberibacter asiaticum. The psyllid itself severely distorts leaves, which become stunted and galled. T. erytreae affects species in the family Rutaceae, occurring on wild hosts as well as on Citrus species. T. erytreae is listed as an A1 quarantine pest by EPPO (OEPP/EPPO, 1988) and is also a quarantine pest for CPPC and OIRSA. The importation of plants for planting and cut branches of citrus from countries where either citrus greening bacterium or either of its vectors occur has been prohibited (OEPP/EPPO, 1990). T. erytreae occurs in Africa and parts of the Middle East but could probably establish and spread in Mediterranean countries without difficulty. Besides its role in citrus greening, the psyllid has itself significant damage potential.

Genomic Epidemiology and Evolution of Escherichia coli in Wild Animals in Mexico

ABSTRACT Escherichia coli is a common bacterial species in the gastrointestinal tracts of warm-blooded animals and humans. Pathogenicity and antimicrobial resistance in E. coli may emerge via host switching from animal reservoirs. Despite its potential clinical importance, knowledge of the population structure of commensal E. coli within wild hosts and the epidemiological links between E. coli in nonhuman hosts and E. coli in humans is still scarce. In this study, we analyzed the whole-genome sequencing data of a collection of 119 commensal E. coli strains recovered from the guts of 55 mammal and bird species in Mexico and Venezuela in the 1990s. We observed low concordance between the population structures of E. coli isolates colonizing wild animals and the phylogeny, taxonomy, and ecological and physiological attributes of the host species, with distantly related E. coli strains often colonizing the same or similar host species and distantly related host species often hosting closely related E. coli strains. We found no evidence for recent transmission of E. coli genomes from wild animals to either domesticated animals or humans. However, multiple livestock- and human-related virulence factor genes were present in E. coli of wild animals, including virulence factors characteristic of Shiga toxin-producing E. coli (STEC) and atypical enteropathogenic E. coli (aEPEC), where several isolates from wild hosts harbored the locus of enterocyte effacement (LEE) pathogenicity island. Moreover, E. coli isolates from wild animal hosts often harbored known antibiotic resistance determinants, including those against ciprofloxacin, aminoglycosides, tetracyclines, and beta-lactams, with some determinants present in multiple, distantly related E. coli lineages colonizing very different host animals. We conclude that genome pools of E. coli colonizing the guts of wild animals and humans share virulence and antibiotic resistance genes, underscoring the idea that wild animals could serve as reservoirs for E. coli pathogenicity in human and livestock infections. IMPORTANCE Escherichia coli is a clinically important bacterial species implicated in human- and livestock-associated infections worldwide. The bacterium is known to reside in the guts of humans, livestock, and wild animals. Although wild animals are recognized as potential reservoirs for pathogenic E. coli strains, the knowledge of the population structure of E. coli in wild hosts is still scarce. In this study, we used fine resolution of whole-genome sequencing to provide novel insights into the evolution of E. coli genomes from a small yet diverse collection of strains recovered within a broad range of wild animal species (including mammals and birds), the coevolution of E. coli strains with their hosts, and the genetics of pathogenicity of E. coli strains in wild hosts in Mexico. Our results provide evidence for the clinical importance of wild animals as reservoirs for pathogenic strains and highlight the need to include nonhuman hosts in the surveillance programs for E. coli infections.

Quantifying the Economic Impact of Bovine Tuberculosis on Livestock Farms in South-Western Spain

Pasture-based livestock farming generates income in regions with limited resources and is key to biodiversity conservation. However, costs derived from fighting disease can make the difference between profit and loss, eventually compromising farm survival. Animal TB (TB), a chronic infection of cattle and other domestic and wild hosts, is one of the primary limitations of beef cattle farming in some parts of Europe. When an animal tests positive for TB, a loss of profit is caused in the farm, which is due mainly to the animal’s slaughter, replacement of the slaughtered animal and the need to immobilize the rest of the herd. We estimated the economic impact in terms of loss of profit as a result of incremental costs and forgone incomes. We show that farms with a larger number of heads are more capable of dealing with the loss of profit caused by the disease. The quantification of the loss of profit contributes to the ongoing debate on the co-sharing of TB costs between government and farmers. The compensation farmers receive from the public administration to mitigate the economic effects of the disease control interventions is only intended to balance the loss due to slaughter of the infected cattle, being the loss of profit a more global concept.