Parasites in biodiversity conservation: friend or foe?

Birds in arid regions have depauperate louse communities: Climate change implications?

Environmental factors such as temperature and humidity influence the distribution of free-living organisms. As climates change, the distributions of these organisms change along with their associated parasites, mutualists and commensals. Less studied, however, is the possibility that environmental conditions may directly influence the distribution of these symbionts even if the hosts are able to persist in altered environments. Here, we investigate the diversity of parasitic lice (Insecta: Phthiraptera) on birds in arid Utah compared to the humid Bahamas. We quantified the parasite loads of 500 birds. We found that the prevalence, abundance and richness of lice was considerably lower among birds in Utah, compared to the Bahamas, despite sampling greater host taxonomic richness in Utah. Our data suggest that as climates change, birds in arid regions will have less diverse louse communities over time, potentially relieving birds of some of the cost of controlling these ectoparasites. Conversely, birds in more humid regions will see an increase in louse diversity, which may require them to invest more time and energy in anti-parasite defense. Additional research with other ectoparasites of birds and mammals across different environmental conditions is needed to more fully understand how climate change may reshape parasite communities, and how these changes could influence their hosts.

A systematic review and meta-analysis on prevalence of gastrointestinal helminthic infections in rodents of Iran: An emphasis on zoonotic aspects

Rodents are the largest group of mammals that adapt to different ecosystems and may act as the potential reservoirs of significant pathogens including gastrointestinal (GI) helminths. Rodent-borne parasitic pathogens have been and remain a great concern for animal and human health. The aim of this systematic review and meta-analysis is thus to clarify and better understand the pooled prevalence of GI helminthic infections and the associated risk factors in rodents in Iran. Multiple databases (PubMed, Scopus, Web of Science, Google Scholar, SID, Magiran and Irandoc) were searched for relevant literature published up to March 2022. A random-effects meta-analysis model was applied to estimate the pooled prevalence with 95 % confidence interval. Moreover, heterogeneity among studies was evaluated using the Cochran's Q test and the I 2-statistic. Out of the 5438 publications searched, 28 articles (30 datasets) were ultimately eligible for inclusion in the study. Thus, 3649 captured rodents belonging to 6 families, 20 genera, and 35 species were examined for GI helminths in Iran. Then, 54 helminth species were identified in the present research, including 33 nematodes, 16 cestodes, 4 trematods, and 1 acanthocephalan. The prevalence rate of GI parasitic infections was 56 % (95 % CI: 50-63 %). Hymenolepis diminuta, Syphacia obvelata and Rodentolepis nana were the most common helminthic infections (13 %, 9 %, and 8 %, respectively). Moreover, 11 potential zoonotic helminths were found. There was no significant difference in pooled prevalence between male and female rodents (P = 0.40). Considering geographical areas, northern and eastern provinces had the highest prevalence of GI helminthic infections among rodents. The prevalence of GI worms in Iranian rodents was as high as 56 % with 11 zoonotic helminths. Therefore, it is suggested to observe the health of the environment, destroy the biological nests of rodents, avoid half-finished constructions, repair and improve streams and sidewalks, organize and collect garbage, and carry out biological and chemical control to handle the population of rodents. Increasing the awareness of local people about the harmful effects of rodents and the ways of transmission and prevention of rodent-borne intestinal worms transmitted to humans should be prioritized in health decisions.

Hepatozoon (Eucoccidiorida: Hepatozoidae) in wild mammals of the Americas: a systematic review

BACKGROUND

The study of parasites provides insight into intricate ecological relationships in ecosystem dynamics, food web structures, and evolution on multiple scales. Hepatozoon Eucoccidiorida: Hepatozoidae) is a genus of protozoan hemoparasites with heteroxenous life cycles that switch infections between vertebrates and blood-feeding invertebrates. The most comprehensive review of the genus was published 26 years ago, and currently there are no harmonized data on the epizootiology, diagnostics, genotyping methods, evolutionary relationships, and genetic diversity of Hepatozoon in the Americas.

METHODS

Here, we provide a comprehensive review based on the PRISMA method regarding Hepatozoon in wild mammals within the American continent, in order to generate a framework for future research.

RESULTS

11 out of the 35 countries of the Americas (31.4%) had data on Hepatozoon, with Carnivora and Rodentia orders having the most characterizations. Bats, ungulates, and shrews were the least affected groups. While Hepatozoon americanum, H. americanum-like, H. canis, H. didelphydis, H. felis, H. milleri, H. griseisciuri, and H. procyonis correspond to the identified species, a plethora of genospecies is pending for a formal description combining morphology and genetics. Most of the vectors of Hepatozoon in the Americas are unknown, but some flea, mite, and tick species have been confirmed. The detection of Hepatozoon has relied mostly on conventional polymerase chain reaction (PCR), and the implementation of specific real time PCR for the genus needs to be employed to improve its diagnosis in wild animals in the future. From a genetic perspective, the V4 region of the 18S rRNA gene has been widely sequenced for the identification of Hepatozoon in wild animals. However, mitochondrial and apicoplast markers should also be targeted to truly determine different species in the genus. A phylogenetic analysis of herein retrieved 18S ribosomal DNA (rDNA) sequences showed two main clades of Hepatozoon: Clade I associated with small mammals, birds, and herpetozoa, and Clade II associated with Carnivora. The topology of the tree is also reflected in the haplotype network.

CONCLUSIONS

Finally, our review emphasizes Hepatozoon as a potential disease agent in threatened wild mammals and the role of wild canids as spreaders of Hepatozoon infections in the Americas.

Aquaculture of Animal Species: Their Eukaryotic Parasites and the Control of Parasitic Infections

Parasites are very diverse and common in both natural populations and in stocks kept in aquacultural facilities. For most cultured species, there are important bacteria and viruses causing diseases, but eukaryotic parasites are also very important. We review the various combinations of aquacultured species and eukaryotic parasitic groups and discuss other problems associated with aquaculture such as eutrophication, zoonotic species, and invasive species, and we conclude that further development of aquaculture in a sustainable manner must include a holistic approach (One Health) where many factors (e.g., human health, food safety, animal health and welfare, environmental and biodiversity protection and marketability mechanisms, etc.) are considered.