Tropical Parasites Research Articles

Population and Transcriptomic Changes of the Tropical Fish Parasite Caligus confusus (Copepoda: Caligidae) with Seasonal Variations in Sea Temperature

Fish–parasite systems could be subject to two scenarios under climate change: (i) increased water temperature might enhance parasite metabolism, allowing the parasite to spread rapidly; (ii) parasitism could decrease if the optimal temperature for growth and transmission is exceeded. Sea lice are parasitic copepods commonly found on marine fish in tropical regions, yet their biology remains poorly investigated. In this study, we analyzed the changes in infection levels and the transcriptomic response of the tropical sea louse Caligus confusus to two seasonal seawater temperatures (30 °C, “warm”, and 21 °C, “cold”). The prevalence of C. confusus was significantly higher in the colder water. A de novo transcriptomic analysis of C. confusus, the first for a tropical sea louse, revealed 426 over-expressed and 1402 down-expressed transcripts at the lower temperature. In particular, we observed over-expression of transcripts encoding vitellogenins (vit-1, vit-2, vit-4, and vit-6) and matrix metalloproteinases (mmp-2 and mmp-9), which are involved in reproduction and development. These results suggest that the cold tropical season physiologically favors C. confusus and that low temperature favors embryo development, which might ultimately lead to a higher prevalence. It is possible, therefore, that climate change could reduce some tropical sea lice populations during extreme warming events.

Novel Lipophilic Hydroxamates Based on Spirocarbocyclic Hydantoin Scaffolds with Potent Antiviral and Trypanocidal Activity.

Flaviviridae infections, such as those caused by hepatitis C (HCV) and dengue viruses (DENVs), represent global health risks. Infected people are in danger of developing chronic liver failure or hemorrhagic fever, both of which can be fatal if not treated. The tropical parasites Trypanosoma brucei and Trypanosoma cruzi cause enormous socioeconomic burdens in Sub-Saharan Africa and Latin America. Anti-HCV chemotherapy has severe adverse effects and is expensive, whereas dengue has no clinically authorized treatment. Antiparasitic medicines are often toxic and difficult to administer, and treatment failures are widely reported. There is an urgent need for new chemotherapies. Based on our previous research, we have undertaken structural modification of lead compound V with the goal of producing derivatives with both antiviral and trypanocidal activity. The novel spirocarbocyclic-substituted hydantoin analogs were designed, synthesized, and tested for antiviral activity against three HCV genotypes (1b, 3a, 4a), DENV, yellow fever virus (YFV), and two trypanosome species (T. brucei, T. cruzi). The optimization was successful and led to compounds with significant antiviral and trypanocidal activity and exceptional selectivity. Several modifications were made to further investigate the structure-activity relationships (SARs) and confirm the critical role of lipophilicity and conformational degrees of freedom.

Biological activities of 4H-thiochromen-4-one 1,1-dioxide derivatives against tropical disease parasites: A target-based drug design approach

A promising strategy for developing novel therapies against tropical diseases, including malaria, leishmaniasis, and trypanosomiasis, is to detect biological targets such as trypanothione reductase, a vital parasite enzyme that regulates oxidative stress. This enzyme is highly selective and conserved in the Trypanosotidae family and has an ortholog in the Plasmodium genus. Previous studies have established that an isosteric replacement of naphthoquinone's carbonyl group with a sulfone group leads to compounds with high bioactivity and selectivity (half-maximal inhibitory concentration = 3 μM against intracellular amastigotes of L. panamensis, selectivity index = 153 over monocytes U-937). In this study, we analyzed the reactive oxygen species (ROS) levels of parasites through indirect measurements of the tryparedoxin system after treatment with these isosteric compounds. This strategy proved that a significant increase in the ROS levels and strong mitochondrial perturbation led to the death of parasites due to cell homeostatic imbalance, confirming the compounds' effectiveness in disrupting this important metabolic pathway. To improve understanding of the parasite-molecule interaction, 27 new compounds were synthesized and assessed against parasites of the three principal tropical diseases (malaria, leishmaniasis, and trypanosomiasis), displaying an EC50 below 10 μM and good correlation with in-silico studies, indicating that the 4H-thiochromen-4-one 1,1-dioxide core is a special allosteric modulator. It can interact in the binding pocket through key amino acids like Ser-14, Leu-17, Trp-21, Ser-109, Tyr-110, and Met-113, leading to interhelical disruption.

Detection of Soil-transmitted Helminths and their Risk Factors in Some Local Government Primary Schools Sokoto, Nigeria

Background: Soil-transmitted helminths are among the neglected tropical disease parasites of humans and one of the major public health burdens in developing countries, particularly Sub-Saharan Africa. It is estimated that about 1.5 billion people are affected worldwide.
 Aims: The study was aimed to determine the prevalence and risk factors of Soil-transmitted helminths infection among primary school children.
 Study Design: This was a cross sectional, descriptive study.
 Place and Duration of Study: The study was conducted among primary school children within the age of 4-15 years old in Sokoto South, Wamakko, Yabo and Dange Shuni local government areas of Sokoto State from February 2021 to July 2021.
 Methodology: Faecal samples of 252 children were collected and analyzed using formol-ether concentration technique.
 Results: An overall prevalence of 6.0% was recorded. Differential prevalence of parasite species showed 6.7% Ascaris lumbricoide, and 93.3% hookworm infection. There was high prevalence among Males (7.2%) than Females (4.0%). The age group 10-12 has the high prevalence of 9.8%. The high prevalence of 9.5% was obtained in Yabo and Sokoto South respectively. Tap water and water closet users have the lowest prevalence of 5.3%. High prevalence of 33.3% was recorded among borehole users contaminated with soil.
 Conclusion: The total low prevalence of soil-transmitted helminths may be as a result of improved awareness of the Soil-transmitted helminths in the study area. The government, non-government agencies should help in the provision of social amenities to ensure the total eradication of these diseases. The teaching of health education in both private and public schools should be encouraged by the government.

Comparative Proteomics and Genome-Wide Druggability Analyses Prioritized Promising Therapeutic Targets against Drug-Resistant Leishmania tropica

Leishmania tropica is a tropical parasite causing cutaneous leishmaniasis (CL) in humans. Leishmaniasis is a serious public health threat, affecting an estimated 350 million people in 98 countries. The global rise in antileishmanial drug resistance has triggered the need to explore novel therapeutic strategies against this parasite. In the present study, we utilized the recently available multidrug resistant L. tropica strain proteome data repository to identify alternative therapeutic drug targets based on comparative subtractive proteomic and druggability analyses. Additionally, small drug-like compounds were scanned against novel targets based on virtual screening and ADME profiling. The analysis unveiled 496 essential cellular proteins of L. tropica that were nonhomologous to the human proteome set. The druggability analyses prioritized nine parasite-specific druggable proteins essential for the parasite's basic cellular survival, growth, and virulence. These prioritized proteins were identified to have appropriate binding pockets to anchor small drug-like compounds. Among these, UDPase and PCNA were prioritized as the top-ranked druggable proteins. The pharmacophore-based virtual screening and ADME profiling predicted MolPort-000-730-162 and MolPort-020-232-354 as the top hit drug-like compounds from the Pharmit resource to inhibit L. tropica UDPase and PCNA, respectively. The alternative drug targets and drug-like molecules predicted in the current study lay the groundwork for developing novel antileishmanial therapies.

Prevalence and Clinical Relevance of Schistosoma mansoni Co-Infection with Mycobacterium tuberculosis: A Systematic Literature Review.

Tuberculosis disease stands for the second leading cause of death worldwide after COVID-19, most active tuberculosis cases result from the reactivation of latent TB infection through impairment of immune response. Several factors are known to sustain that process. Schistosoma mansoni, a parasite of the helminth genus that possesses switching power from an immune profile type Th1 to Th2 that favors reactivation of latent TB bacteria. The aim of the study was to assess the prevalence of the co-infection between the two endemic infections. Systematic literature was contacted at the University Clinical Research Center at the University of Sciences, Techniques, and Technologies of Bamako in Mali. Original articles were included, and full texts were reviewed to assess the prevalence and better understand the immunological changes that occur during the co-infection. In total, 3530 original articles were retrieved through database search, 53 were included in the qualitative analysis, and data from 10 were included in the meta-analysis. Prevalence of the co-infection ranged from 4% to 34% in the literature. Most of the articles reported that immunity against infection with helminth parasite and more specifically Schistosoma mansoni infection enhances latent TB reactivation through Th1/Th2. In sum, the impact of Schistosoma mansoni co-infection with Mycobacterium tuberculosis is under-investigated. Understanding the role of this endemic tropical parasite as a contributing factor to TB epidemiology and burden could help integrate its elimination as one of the strategies to achieve the END-TB objectives by the year 2035.

Environmental DNA in human and veterinary parasitology - Current applications and future prospects for monitoring and control

Parasites are important pathogens with significant global economic, public and animal health impacts. Successful control or elimination of many parasitic diseases, not least neglected tropical parasites, will require scalable, sensitive and cost-effective monitoring tools. Environmental DNA (eDNA) methods, used extensively in ecology for biomonitoring in natural ecosystems, offer promising advantages such reduced costs and labor requirements for species monitoring. Yet, the use of eDNA-based methods in parasitology and disease surveillance, has only recently begun to be explored. With this review, we wish to give an up-to-date overview of current uses and limitations of eDNA in human and veterinary parasitology, and how existing challenges can be overcome to fully utilize the potential of eDNA for monitoring and control of parasitic diseases. We begin by systematically searching published literature to identify studies that apply eDNA methods in parasitology and synthesize the main findings from these studies. We find that eDNA applications in parasitology only account for a small proportion (73/1960) of all eDNA publications up to now, and even fewer (27/73) studies, that apply eDNA methods specifically for parasites of human or veterinary importance. The majority of studies concern snail-borne trematodes and their intermediate host snails, while a few apply eDNA for mosquito vector species detection. A strong geographical bias, with only very few studies undertaken on the African continent, where parasites are of the biggest public health concern, is also noted. Current obstacles hindering further advances of eDNA methods in parasitology include incomplete reference databases, and challenges related to real-time monitoring in remote areas, and in certain LMIC settings. Finally, we point to future opportunities for eDNA-based research in parasitology and highlight recent innovations in eDNA research, which could further develop its application for monitoring and control of parasitic diseases and vectors in the future.

Novel Electrochemical Biosensing for Detection of Neglected Tropical Parasites of Animal Origin: Recent Advances

AbstractParasitic diseases are among neglected disease of human and animals, especially in tropical and sub tropical regions. In the era of artificial intelligence, the novel biosensing diagnostic platform is needed for an early control measure implementation. This goal can be successfully achieved by onsite application of electrochemical biosensors. They are being developed towards point of care diagnostics; however commercial availability is scanty. The recent developments during last one decade in terms of the electrode surface modification for rapid diagnosis of important emerging/re‐emerging parasites is presented. The information would help future improvement in the electrochemical biosensing of parasites.

PERFORMAN BCS KERBAU LUMPUR DOMPU (Swamp Buffalo) JANTAN DAN BETINA DIBERIKAN PAKAN LIMBAH JAGUNG SECARA EKSTENSIF DI KABUPATEN DOMPU NTB

Buffalo (Bubalus bubalis) is one of the large ruminants that have an important contribution in the development of national livestock. Local buffalo has its own advantages to be developed because it can survive on low-quality feed, is tolerant of tropical parasites and its existence has been integrated with the life of farmers in rural areas. The research has been carried out for 8 months starting from July 16, 2015 to March 16, 2016, with an allocation of 240 days of data collection in the field to determine the BCS performance of male and female mud buffaloes fed corn waste extensively in Dompu Regency, NTB. The observed variable was the performance of BCS Buffalo Mud (Swamp Buffalo) male and female given extensive corn waste feed in Dompu Regency, West Nusa Tenggara. The results showed that in the age group of 7-12 months, there was a significant difference (p<0.05) between BCS of female buffalo in Dompu (4.80±0.45) compared to BCS of female buffalo in Manggelewa (4.10±0.66). However, in the age group 7-12 months, the BCS of male buffalo Doro Ncanga in Manggelewa (4.31±0.66) was greater (p<0.05) than the BCS of buffalo in Kempo (4.19±0.75) and Dompu (3.58±0.76).

Sequestration and Cyanobacterial Diet Preferences in the Opisthobranch Molluscs Dolabrifera nicaraguana and Stylocheilus rickettsi

A multidisciplinary approach was used to assess chemical ecological dietary interactions between marine organisms as a tool to isolate novel ecologically relevant compounds with biotechnological potential. First, laboratory-based feeding preference assays of the sea hareDolabrifera nicaraguana(previously known asD. dolabrifera), an anaspidean mollusc, were conducted by simultaneously offering six food options collected from nearby tidal pools in the Coiba National Park in the Tropical Eastern Pacific of Panama. An evaluation of preferred dietary repertoire revealedD. nicaraguanasignificantly preferred cf.Lyngbyasp. over the cyanobacteriumSymplocasp., green algaChaetomorphasp., and red algaSpyridiasp. A no-choice feeding assay using cf.Lyngbyasp. or green algaCladophorasp. supported this finding. Secondly, we conducted bioactivity-guided fractionation using the preferred food source ofD. nicaraguana, the ‘hair-like” cf.Lyngbyasp. from which we also isolated and elucidated two new depsipeptide compounds, veraguamide M (1) and veraguamide N (2). Veraguamides M (1) and N (2) showedin vitroactivity toward the malaria-causing parasitePlasmodium falciparumwith GI50values of 4.2 and 4.3 μM, respectively, and therapeutic windows of 7.0–8.0 (based on moderate cytotoxicities to mammalian Vero cells with GI50values of 29.3 and 34.1 μM, respectively). Veraguamide N (2) was also active againstLeishmania donovani, the causative agent of visceral leishmaniasis, with a GI50value of 6.9 μM. We then evaluated sequestration of these new compounds byD. nicaraguanaused in the feeding assays and found trace amounts of the dietary sequestered compounds. Finally, we evaluated sequestration of these new compounds by the sea hareStylocheilus rickettsi(previously known asS. striatus) that were grazing on the cf.Lyngbyasp. used in the feeding assays and found both to be sequestered. This study is the first example whereby compounds with significant activity against tropical parasites have been found in both the sea hareS. rickettsiand its cyanobacterial food source. These results suggest that chemical ecological studies involving sea hares and cyanobacteria continue to provide a diverse source of bioactive compounds with biotechnological potential.

The Impact of Temperature on the Sporogonic Development of the Tropical Avian Malaria Parasite Plasmodium relictum (Genetic Lineage pGRW4) in Culex pipiens Form molestus Mosquitoes

The avian malaria parasite Plasmodium relictum (genetic lineage pGRW4) is known to cause severe pathology in nonadapted vertebrate hosts. This parasite is prevalent in some bird species in Northern Europe, however the records obtained are only from adult long-distance migrant birds after their return from the wintering grounds. A recent experimental study showed that this parasite completes sporogonic development in the local European vector Culex pipiens at a controlled mean temperature of 19 °C. Thereby, temperature limits for the transmission of this parasite in Northern Europe remain unknown. In this study, we took a step further and tested the impact of different temperature conditions, including some extreme fluctuations between 23 °C down to 7 °C, on the sporogonic development of P. relictum (pGRW4) in the vector Culex pipiens form molestus. Mosquitoes were exposed to infection and kept under different air-temperature conditions: (i) constant warm temperature, (ii) natural outdoor temperatures and (iii) temporary exposure to low temperatures. Plasmodium relictum (pGRW4) completed sporogony in mosquitoes of all experimental groups, however different patterns of the sporogonic development depending on temperature conditions were observed. Based on these results, we conclude that the cool air temperature of Northern Europe in summer is not a limiting factor in successful development of the parasite. However, delayed sporogony caused by low summer temperatures may have a detrimental impact on the active transmission of this parasite in Northern Europe.

The Truman Show for protozoan parasites: A review of in vitro cultivation platforms.

Protozoan parasites are responsible for severe disease and suffering in humans worldwide. Apart from disease transmission via insect vectors and contaminated soil, food, or water, transmission may occur congenitally or by way of blood transfusion and organ transplantation. Several recent outbreaks associated with fresh produce and potable water emphasize the need for vigilance and monitoring of protozoan parasites that cause severe disease in humans globally. Apart from the tropical parasite Plasmodium spp., other protozoa causing debilitating and fatal diseases such as Trypanosoma spp. and Naegleria fowleri need to be studied in more detail. Climate change and socioeconomic issues such as migration continue to be major drivers for the spread of these neglected tropical diseases beyond endemic zones. Due to the complex life cycles of protozoa involving multiple hosts, vectors, and stringent growth conditions, studying these parasites has been challenging. While in vivo models may provide insights into host–parasite interaction, the ethical aspects of laboratory animal use and the challenge of ready availability of parasite life stages underline the need for in vitro models as valid alternatives for culturing and maintaining protozoan parasites. To our knowledge, this review is the first of its kind to highlight available in vitro models for protozoa causing highly infectious diseases. In recent years, several research efforts using new technologies such as 3D organoid and spheroid systems for protozoan parasites have been introduced that provide valuable tools to advance complex culturing models and offer new opportunities toward the advancement of parasite in vitro studies. In vitro models aid scientists and healthcare providers in gaining insights into parasite infection biology, ultimately enabling the use of novel strategies for preventing and treating these diseases.

Early Stages of Drug Discovery in an Academic Institution and Involvement of Pharma for Advancing Promising Leads.

In this Viewpoint, we provide a brief description of two efforts to develop drugs to treat diseases caused by tropical parasites (Malaria, human African trypanosomiasis and Chagas disease). These efforts are largely based in a University setting but draw heavily on Pharma for a complete progression from drug hit discovery to advancement toward clinical trials. The first case is the development of protein farnesyltransferase inhibitors, and the second case is a series of benzthiazoles, the target of which is being investigated.

TINGKAH LAKU KERBAU LUMPUR (BEHAVIOR) YANG DIPELIHARA SECARA EKSTENSIF DI PADANG SABANA DORO NCANGA KAWASAN TAMBORA KABUPATEN DOMPU NUSA TENGGARA BARAT

Buffalo (Bubalus bubalis) is one of the large ruminants that havesignificant contribution in the development of national livestock. Buffalohas its own advantages to be developed because it can survive withlow-quality feed, tolerant of tropical parasites and their presence has beenintegrated with the life of farmers in the countryside. In Dompu Regency, the buffalo populationmostly concentrated in the Doro Ncanga savanna in the Tambora area. InIn this field, buffaloes are generally kept extensively and their presence is much moreearlier than cattle.The purpose of this study was to determine the eating behavior and wallowing behaviorin the Doro Ncanga savanna, Dompu Regency, NTB. The research results are shownin Figure 4.2, namely eating activities and kissing, grabbing, chewing,and swallow food. Wallowing activity at two locations at Hodo and Mada Oi . springsRao is shown in (Figures 4.3, 4.4, and 4.5). In the morning starting at 07:30 -08:35 WITA a herd of buffalo departs hand in hand to the puddle and in the afternoonaround 17:00 - 18:30 pm climb back up to the slopes of the mountains or hills inMount Tambora area. Doro Ncanga's buffalo wallow time at both locationsit is different. The herd of mud buffalo heading towards Mada Oi Rao (Figure 4.6) beginswallowing at 09:30 to 15:00 local time, while in the Mada Oi Hodo puddle (Picture 4.7)start to wallow at 09:00 - 15:30 pm, and there is no time difference between the twothe puddle. In the afternoon at the two puddles (Hodo and Mada Oi Rao) respectivelybuffalo will go up to the hill at 17:00 - 18:30 pm to rest andgraze on (Figure 4.8). In the evening until the morning from 18:00 to06:00 in the morning the buffalo resting or chewing is shown (Figure 4.9).

Experimental study of newly described avian malaria parasite Plasmodium (Novyella) collidatum n. sp., genetic lineage pFANTAIL01 obtained from South Asian migrant bird

BackgroundAvian malaria parasites are microorganisms parasitizing erythrocytes and various tissues of the birds; they are common and distributed worldwide. These parasites are known to infect birds of different taxa and be the cause of the deaths of birds in the wild and in captivity. The species of parasites with the ability to colonize new territories and infect local non-migratory birds are of particular interest. This scenario is likely in temperate zones of Europe, because of climate change and its contribution in spreading vectors of southern origin, which can be involved in the transmission of malaria parasites. In the present study, a tropical Plasmodium parasite from a naturally infected long-distance migrant bird was isolated and tested for its ability to develop in common species of mosquitoes and European short-distance migrant birds.MethodsPlasmodium sp. (pFANTAIL01) was isolated on the Curonian spit of the Baltic sea coast from the naturally infected Common rosefinch, Carpodacus erythrinus in June 2019. The parasite was described based on the morphological features of its blood stages, the partial mitochondrial cytochrome b gene and development after experimental infection of birds and mosquitoes. The parasite was inoculated into Eurasian siskins, Carduelis spinus. Parasitaemia, haematocrit and weight of birds were monitored. At the end of the survey, internal organs were collected to study exoerythrocytic stages of this parasite. Experimental infection of mosquitoes Culex pipiens form molestus and Culex quinquefasciatus was applied to study sporogonic development of the parasite.ResultsBased on morphological features, the parasite was described as a new species, Plasmodium collidatum n. sp., and attributed to subgenus Novyella. It was revealed that the obtained pFANTAIL01 lineage is a generalist parasite infecting a wide range of avian hosts and most likely is transmitted in South and Southeast (SE) Asia and Oceania. In Europe, this strain was recorded only in adult migratory birds wintering in South Asia. This parasite developed high parasitaemia in experimentally infected siskins and caused 25 % mortality. Exoerythrocytic stages of pFANTAIL01 were found in the lungs, liver, spleen and kidney of the deceased birds. Sporogonic development did not occur in Cx. pipiens form molestus and Cx. quinquefasciatus mosquitoes.ConclusionsPlasmodium collidatum is a highly virulent for Eurasian siskin and completes its development in these birds, which can be considered as a potential vertebrate host if the transmission of the infection starts occurring in Europe and temperate zones.

Dynamic evolution of transposable elements, demographic history, and gene content of paleognathous birds.

Palaeognathae includes ratite and tinamou species that are important for understanding early avian evolution. Here, we analyzed the whole-genome sequences of 15 paleognathous species to infer their demographic histories, which are presently unknown. We found that most species showed a reduction of population size since the beginning of the last glacial period, except for those species distributed in Australasia and in the far south of South America. Different degrees of contraction and expansion of transposable elements (TE) have shaped the paleognathous genome architecture, with a higher transposon removal rate in tinamous than in ratites. One repeat family, AviRTE, likely underwent horizontal transfer from tropical parasites to the ancestor of little and undulated tinamous about 30 million years ago. Our analysis of gene families identified rapid turnover of immune and reproduction-related genes but found no evidence of gene family changes underlying the convergent evolution of flightlessness among ratites. We also found that mitochondrial genes have experienced a faster evolutionary rate in tinamous than in ratites, with the former also showing more degenerated W chromosomes. This result can be explained by the Hill-Robertson interference affecting genetically linked W chromosomes and mitochondria. Overall, we reconstructed the evolutionary history of the Palaeognathae populations, genes, and TEs. Our findings of co-evolution between mitochondria and W chromosomes highlight the key difference in genome evolution between species with ZW sex chromosomes and those with XY sex chromosomes.

Strongyloidiasis in Africa: Systematic Review and Meta-Analysis on Prevalence, Diagnostic Methods, and Study Settings.

Background Strongyloidiasis is an intestinal parasitic infection mainly caused by Strongyloides stercoralis. Although it is a predominant parasite in tropics and subtropics where sanitation and hygiene are poorly practiced, the true prevalence of strongyloidiasis is not known due to low-sensitivity diagnostic methods. Objective This systematic review and meta-analysis is aimed at determining the pooled prevalence of strongyloidiasis in African countries, stratified by diagnostic methods, study settings, and patients. Methods Cross-sectional studies on strongyloidiasis published in African countries from the year 2008 up to 2018 in PubMed and Google Scholar databases and which reported at least one Strongyloides spp. infection were included. Identification and screening of eligible articles were also done. Articles whose focus was on strongyloidiasis in animals, soil, and foreigners infected by Strongyloides spp. in Africa were excluded. The random effects model was used to calculate the pooled prevalence of strongyloidiasis across African countries as well as by diagnostic methods and study settings. The heterogeneity between studies was also computed. Result A total of 82 studies were included. The overall pooled prevalence of strongyloidiasis was 2.7%. By individual techniques, the pooled prevalence of strongyloidiasis was 0.4%, 1.0%, 3.4%, 9.3%, 9.6%, and 19.4% by the respective direct saline microscopy, Kato-Katz, formol ether concentration, polymerase chain reaction, Baermann concentration, and culture diagnostic techniques. The prevalence rates of strongyloidiasis among rural community, school, and health institution studies were 6.8%, 6.4%, and 0.9%, respectively. The variation on the effect size comparing African countries, diagnostic methods, study settings, and patients was significant (P ≤ 0.001). Conclusions This review shows that strongyloidiasis is overlooked and its prevalence is estimated to be low in Africa due to the use of diagnostic methods with low sensitivity. Therefore, there is a need for using a combination of appropriate diagnostic methods to approach the actual strongyloidiasis rates in Africa.

Importation of cats and risk of parasite spread: a Caribbean perspective and case study from St Kitts

BackgroundIn more recent years, international travel with cats has increased. The distribution of cat parasites can change with this movement. Already, subtropical and tropical parasites have been reported by veterinarians in areas where they are not naturally present. Understanding the prevalence of tropical and subtropical parasites in Caribbean islands and the risk of importation to temperate areas could enable improved prevention recommendations and border control import requirements.MethodsWe present a study focused on cat owning students enrolled in a Doctor of Veterinary Medicine (DVM) programme on St Kitts. Owners were interviewed about their cats and their use of parasiticides. Cats were examined for Trichuris felis and Platynosomum fastosum using sugar flotation, Lynxacarus radovskyi using an adhesive tape test, and Dirofilaria immitis using commercial antigen and antibody tests.ResultsData on 115 cats owned by 87 DVM students were collected and 90 cats, all expected to travel to the USA, were examined. Most of the cats were adults and born in St Kitts. Prevalence was reported as 6.8% (95% confidence interval (CI): 2.2–15.1%) for T. felis, 16.2% (95% CI: 8.7–26.6%) for P. fastosum and 6.8% (95% CI: 2.5–14.3%) for L. radovskyi. All D. immitis tests were negative. DVM students reported a high level of deworming (83.3% of the cats), but the number of cats treated per recommendations were low (56.1% for endoparasites and 70.8% for ectoparasites). Also, there was a lack of clarity regarding the purpose of the treatments used and treatments did not appear to be targeted for the parasites present.ConclusionOur results indicate a low prevalence of the parasites of interest in the DVM student cat population compared to other prevalence studies from the Caribbean. However, a degree of non-compliance with parasiticide uses and the high number of cats traveling to the USA indicate a medium risk of importation of tropical and subtropical cat parasites to temperate areas. We recommend stronger health inspections and health screening requirements at the borders including the development of specific parasiticide protocols for cat importation.

Lipophilic Guanylhydrazone Analogues as Promising Trypanocidal Agents: An Extended SAR Study.

In this report, we extend the SAR analysis of a number of lipophilic guanylhydrazone analogues with respect to in vitro growth inhibition of Trypanosoma brucei and Trypanosoma cruzi. Sleeping sickness and Chagas disease, caused by the tropical parasites T. brucei and T. cruzi, constitute a significant socioeconomic burden in low-income countries of sub-Saharan Africa and Latin America, respectively. Drug development is underfunded. Moreover, current treatments are outdated and difficult to administer, while drug resistance is an emerging concern. The synthesis of adamantane-based compounds that have potential as antitrypanosomal agents is extensively reviewed. The critical role of the adamantane ring was further investigated by synthesizing and testing a number of novel lipophilic guanylhydrazones. The introduction of hydrophobic bulky substituents onto the adamantane ring generated the most active analogues, illustrating the synergistic effect of the lipophilic character of the C1 side chain and guanylhydrazone moiety on trypanocidal activity. The n-decyl C1-substituted compound G8 proved to be the most potent adamantane derivative against T. brucei with activity in the nanomolar range (EC50=90 nM). Molecular simulations were also performed to better understand the structure-activity relationships between the studied guanylhydrazone analogues and their potential enzyme target.

1607 The Hidden Parasite

INTRODUCTION: Parasite identification during routine colon cancer screening is unexpected and rather unusual. Schistosoma is a tropical parasite associated to freshwater snails; among which S. mansoni and S. japonicum species have been associated with intestinal tract infection. Although most patients are asymptomatic, identification is crucial to avoid possible complications like chronic intestinal schistosomiasis or hepatosplenic schistosomiasis. CASE DESCRIPTION/METHODS: A 57-year-old Puerto Rican Vietnam veteran with history of schizophrenia and chronic liver disease secondary to Hepatitis C underwent colonoscopy for average-risk colorectal cancer screening. During colonoscopy, a one-centimeter polyp at 15cm was completely removed by hot snare and six additional small sessile polyps in the rectum by cold forceps. Pathology was remarkable for a tubular adenoma, while one of the rectal polyps identified a non-necrotizing granuloma suggestive of schistosoma parasite. Patient had shown no GI symptoms or complaints and was treated with Praziquantel. DISCUSSION: Puerto Rico is an endemic area for schistosoma. Schistosomiasis is a chronic parasitic disease with significant cause of morbidity and mortality. Intestinal polyps and dysplasia can arise due to granulomatous inflammation surrounding eggs deposited in the bowel wall. Gastrointestinal manifestations may result in chronic abdominal pain, poor appetite, and diarrhea for which early identification is necessary for treatment even in the asymptomatic setting.