Biology subjects

Zohdy, S.

Publications and source records attributed to Zohdy, S..

4 recordsLinked to original sources

bioRxiv2022

Mosquito invasion via the global shipping network is slowed in high-risk areas by on-shore and ship-board monitoring

The global shipping network (GSN) has been suggested as a pathway for the establishment and reintroduction of Aedes aegypti and Aedes albopictus primarily via the tire trade. We used historical maritime movement data in combination with an agent-based model to understand invasion risk in the United States Gulf Coast and how the risk of these invasions could be reduced. We found a strong correlation between the total number of cargo ship arrivals at each port and likelihood of arrival by both Ae. aegypti and Ae. albopictus. Additionally, in 2012, 99.2% of the arrivals into target ports had most recently visited ports occupied by both Ae. aegypti and Ae. albopictus, increasing risk of Aedes invasion. Model results indicated that detection and removal of mosquitoes from containers when they are unloaded at a port may be more effective in reducing the establishment of mosquito populations compared to eradication efforts that occur while onboard the vessel, suggesting detection efforts should be focused on unloaded containers. To reduce the risk of invasion and reintroduction of Ae. aegypti and Ae. albopictus, surveillance and control efforts should be employed when containers leave high risk locations and when they arrive in ports at high risk of establishment.

ecology↗

bioRxiv2022

Parasite and pathogen prevalence in our closest animal companions is determined by accessibility of sanitation services

Despite the critical role parasites play in ecosystem functioning and their considerable influence on human society, little is known about their variations in abundance on a global scale. This gap in knowledge is amplified by a lack of holistic understanding on how the abundance of parasites of wildlife and humans varies across environmental and socioeconomic gradients, despite a need to integrate study of parasites across social and environmental spheres. Free-roaming companion animals (e.g., domestic cats (Felis catus) and dogs (Canis lupus familiaris)) share pathogens and have frequent contact with humans and wildlife. Thus, they are an effective model to understand how parasite and pathogen prevalence of humans and wildlife varies across environmental and socioeconomic gradients. Through a global systematic review and analysis of socioeconomic and environmental variables, including per capita GDP, income disparity, sanitation, biodiversity, island habitation, and latitude, we find that sanitation and island habitation best explained free-roaming companion animal parasite and pathogen prevalence. Sanitation was significantly associated with parasite and pathogen prevalence in free-roaming companion animals, such that for every 10% increase in the proportion of the human population with improved sanitation access, parasite and pathogen prevalence in free-roaming companion animals decreased by 12% (5-19%, 95% C.L.; p = 0.0023). Since companion animals share many parasites with humans and wildlife, these results suggest that actionable interventions to improve sanitation access could reduce parasite and pathogen exposure risks from companion animals to humans and wildlife. Significance StatementIn addition to playing a critical role in ecosystem functioning, parasites also influence human health, behavior, and society. Further, parasites are also impacted by human activities, as much as by ecological phenomena in natural environments. Despite these dualities, little is known about their variations in abundance on a global scale across environmental and socioeconomic gradients. Using free-roaming companion animals (e.g., domestic cats (Felis catus) and dogs (Canis lupus familiaris)) as a model system, we find that access to safely managed sanitation services is strongly associated with parasite and pathogen prevalence. This finding underscores improvements to sanitation as an actionable One Health intervention that could reduce parasite and pathogen exposure risks from companion animals to humans and wildlife.

ecology↗

bioRxiv2021

Using marine cargo traffic to identify countries in Africa with greatest risk of invasion by Anopheles stephensi

Anopheles stephensi is an efficient malaria vector commonly found in South Asia and the Arabian Peninsula, but in recent years it has established as an invasive species in the Horn of Africa (HoA). In this region, An. stephensi was first detected in a livestock quarantine station near a major seaport in Djibouti in 2012, in Ethiopia in 2016, in Sudan in 2018 and Somalia in 2019. Anopheles stephensi often uses artificial containers as larval habitats, which may facilitate introduction through maritime trade as has been seen with other invasive container breeding mosquitoes. If An. stephensi is being introduced through maritime traffic, prioritization exercises are needed to identify locations at greatest risk of An. stephensi introduction for early detection and rapid response, limiting further invasion opportunities. Here, we use UNCTAD maritime trade data to 1) identify coastal African countries which were most highly connected to select An. stephensi endemic countries in 2011, prior to initial detection in Africa, 2) develop a ranked prioritization list of countries based on likelihood of An. stephensi introduction for 2016 and 2020 based on maritime trade alone and maritime trade and habitat suitability, and 3) use network analysis to describe intracontinental maritime trade and eigenvector centrality to determine likely paths of further introduction on the continent if An. stephensi is detected in a new location. Our results show that in 2011, Sudan and Djibouti were ranked as the top two countries with likelihood of An. stephensi introduction based on maritime trade alone, and these were indeed the first two coastal countries in the HoA where An. stephensi was detected. Trade data from 2020 with Djibouti and Sudan included as source populations identify Egypt, Kenya, Mauritius, Tanzania, and Morocco as the top five countries with likelihood of An. stephensi introduction. When factoring in habitat suitability, Egypt, Kenya, Tanzania, Morocco, and Libya are ranked highest. Network analysis revealed that the countries with the highest eigenvector centrality scores, and therefore highest degrees of connectivity with other coastal African nations were South Africa (0.175), Mauritius (0.159), Ghana (0.159), Togo (0.157), and Morocco (0.044) and therefore detection of An. stephensi in any one of these locations has a higher potential to cascade further across the continent via maritime trade than those with lower eigenvector centrality scores. Taken together, these data could serve as tools to prioritize efforts for An. stephensi surveillance and control in Africa. Surveillance in seaports of countries at greatest risk of introduction may serve as an early warning system for the detection of An. stephensi, providing opportunities to limit further introduction and expansion of this invasive malaria vector in Africa.

ecology↗

bioRxiv2021

Tracking of Anopheles stephensi in Ethiopia using mitochondrial DNA reveals pattern of spread

The recent detection of the South Asian malaria vector Anopheles stephensi in the Horn of Africa (HOA) raises concerns about the impact of this mosquito on malaria transmission in the region. The mode and history of introduction is important for predicting the likelihood of continued introduction and future spread. Analysis of An. stephensi genetic diversity and population structure can provide insight into the history of the mosquito in the HOA. We investigated genetic diversity of An. stephensi in eastern Ethiopia where detection suggests a range expansion to this region to understand the history of this invasive population. We sequenced the cytochrome oxidase subunit I (COI) and cytochrome B gene (CytB) in 187 An. stephensi collected from 10 sites in Ethiopia in 2018. Phylogenetic analyses using a maximum-likelihood approach and minimum spanning network were conducted for Ethiopian sequences. Molecular identification of bloodmeal sources was also performed using universal vertebrate CytB sequencing. Six COI-CytB haplotypes were observed based on five segregating sites, with the highest number of haplotypes in the northeastern sites (Semera, Bati, and Gewana towns) relative to the southeastern sites (Kebridehar, Godey, and Degehabur) in eastern Ethiopia. In the phylogenetic and network analysis, we observed population differentiation based on the distribution of the haplotypes across the northeastern and central sites (Erer Gota, Dire Dawa, and Awash Sebat Kilo) compared to the southeastern sites and evidence of a South Asian origin of the HOA An. stephensi lineages. The presence of the putative South Asian haplotype of origin at sites closest to Ethiopias northeastern borders support route of introductions into Ethiopia from the northeast. Finally, molecular bloodmeal analysis revealed evidence of feeding on bovines, goats, dogs, and humans, as well as evidence of multiple (mixed) blood meals. In conclusion, we find support for the hypothesis for the recent expansion of An. stephensi into southeastern Ethiopia with multiple introductions. We also find evidence that supports the hypothesis that HOA An. stephensi populations originate from South Asia rather than the Arabian Peninsula. The evidence of both zoophagic and anthropophagic feeding support the potential for livestock movement to play a role in vector spread in this region.

ecology↗