Male Parasites Research Articles

Are sexes equally parasitized in damselflies and dragonflies?

Parasitism plays an essential part in ecology and evolution of host species and understanding the reasons for differential parasitism within and among hosts species is therefore important. Among the very important factors potentially affecting parasitism is the gender of the host. Here, we studied whether either females or males are more likely to harbour parasites among Odonatan insects, by relying on an extensive literature review and new field data. We collected data on numerous dragonfly and damselfly species and their ectoparasites (water mites) and endoparasites (gregarines) to examine the generality of similarities and differences in prevalence, intensity and maximum number of parasites of male and female hosts. We found three main results. Firstly, most of the odonate host species showed no differences between sexes in either gregarine or water mite prevalence and intensity. The only exception was female damselflies’ higher gregarine prevalence and intensity compared to conspecific males. These inequalities in gregarine parasitism may be due to behavioral and physiological differences between conspecific males and females. In comparison, there were no differences in dragonflies between sexes in water mite or gregarine prevalence and intensity. Secondly, damselflies had higher prevalence and intensity levels of both gregarine and water mite parasites compared to dragonflies. Finally, we found a strong species level pattern between female and male parasitism: a certain level of gregarine or water mite parasitism in one sex was matched with a similar parasitism level for the other. This indicates similar exposure and susceptibility to parasites on both sexes. Even though significant differences of parasite levels between the sexes were observed within certain host species, our results strongly suggest that on a general level a more parasitized sex does not exist in the order, Odonata.

Population-Specific Covariation between Immune Function and Color of Nesting Male Threespine Stickleback.

Multiple biological processes can generate sexual selection on male visual signals such as color. For example, females may prefer colorful males because those males are more readily detected (perceptual bias), or because male color conveys information about male quality and associated direct or indirect benefits to females. For example, male threespine stickleback often exhibit red throat coloration, which females prefer both because red is more visible in certain environments, and red color is correlated with male immune function and parasite load. However, not all light environments favor red nuptial coloration: more tannin-stained water tends to favor the evolution of a melanic male phenotype. Do such population differences in stickleback male color, driven by divergent light environments, lead to changes in the relationship between color and immunity? Here, we show that, within stickleback populations, multiple components of male color (brightness and hue of four body parts) are correlated with multiple immune variables (ROS production, phagocytosis rates, and lymphocyte:leukocyte ratios). Some of these color-immune associations persist across stickleback populations with very different male color patterns, whereas other color-immune associations are population-specific. Overall, lakes with red males exhibit stronger color-immune covariance while melanic male populations exhibit weak if any color-immune associations. Our finding that color-immunity relationships are labile implies that any evolution of male color traits (e.g., due to female perceptual bias in a given light environment), can alter the utility of color as an indicator of male quality.

Temporal variation in population structure of the isopod Urobopyrus processae Richardson, 1904 (Isopoda: Bopyridae) infesting the branchial chamber of the night shrimp Ambidexter symmetricus Manning and Chace, 1971 (Decapoda: Processidae)

Caridean shrimps are often infested by ectoparasites from the isopod family Bopyridae. Urobopyrus processae is a widespread species of bopyrid parasitizing the branchial (gill) chambers of members of the caridean family Processidae, including Ambidexter symmetricus. We examined hypotheses on differential infestation based on gender, castration of the host by the parasite, correlation between host and parasite size, and the fecundity of female parasites. Infestation rates varied from 1.3 to 32.1% between 2010 and 2011. Infested shrimps ranged from 1.26 mm to 6.24 mm carapace length (CL) between 2010 and 2011. Female shrimps were infested at a higher rate than males (2010 P = 0.0376; 2011 P = 0.0023). We report for the first time the differential selection between left and right branchial chambers in a caridean shrimp by a bopyrid parasite (P = 0.0209). Female parasite total length (TL) increased with host size (CL) in both years of sampling (2010 R2adj = 0.6863; 2011 R2adj= 0.8206). The size of male parasite TL was explained by both host CL (2010 R2adj = 0.4591; 2011 R2adj = 0.5490) and parasite female TL (2010 R2adj = 0.5606; 2011 R2adj = 0.6195). The number of embryos in a brood of the female parasite (85-3096) was varied positively with female TL (R2adj = 0.625). Our results show that the bopyrid-shrimp host relationship in processids is typical of those studied in other carideans, indicating similar selective pressures act on bopyrids infesting the branchial chambers of shrimps.

Social status, immune response and parasitism in males: a meta-analysis.

In male vertebrates, two conflicting paradigms—the energetic costs of high dominance rank and the chronic stress of low rank—have been proposed to explain patterns of immune function and parasitism. To date, neither paradigm has provided a complete explanation for status-related differences in male health. Here, we applied meta-analyses to test for correlations between male social status, immune responses and parasitism. We used an ecoimmunological framework, which proposes that males should re-allocate investment in different immune components depending on the costs of dominance or subordination. Spanning 297 analyses, from 77 studies on several vertebrate taxa, we found that most immune responses were similar between subordinate and dominant males, and neither dominant nor subordinate males consistently invested in predictable immune components. However, subordinate males displayed significantly lower delayed-type hypersensitivity and higher levels of some inflammatory cytokines than dominant males, while dominant males exhibited relatively lower immunoglobulin responses than subordinate males. Despite few differences in immunity, dominant males exhibited consistently higher parasitism than subordinate males, including protozoan blood parasites, ectoparasites and gastrointestinal helminths. We discuss our results in the context of the costs of dominance and subordination and advocate future work that measures both parasitism and immune responses in wild systems.

Is there a sex-specific difference between parasitic chicks in begging behaviour?

Offspring of birds and mammals demand food from their parents through an array of movements and vocalisations known collectively as begging behaviour. We explored sex-specific differences in the begging behaviour of a brood parasite, the common cuckoo (Cuculus canorus), fostered by the great reed warbler (Acrocephalus arundinaceus). As adult male parasites are larger than female parasites, we predicted that male chicks would vocalise more than female chicks. We also predicted a higher frequency of pecking in male chicks than female chicks, and in older compared to younger chicks. Pecking was considered to be any sudden attack of the parasite directed at the head or body of the hosts. Our observations confirmed that there were no sex-specific differences in nestling begging vocalisation and that older chicks tended to deliver more pecks at their hosts than younger ones. One explanation for the lack of intersexual differences in begging vocalisation is that the common cuckoo is an evictor parasite which does not need to compete for food. Alternatively, both male and female cuckoos might already beg at their maximum intensity or have similar food requirements. Moreover, the pecking behaviour in older nestlings could be a strategy to obtain more food from hosts without increasing host-present begging vocalisation.

Host size constrains growth patterns in both female and male Ceratothoa italica, a mouth-dwelling isopod

Host–parasite associations are among the primary drivers of evolutionary diversification, and hold considerable importance for understanding ecological equilibria. In particular, crustacean ectoparasites are typically associated with many fish families, and may, under certain conditions, pose threats to fisheries and aquaculture. Cymothoid isopods include blood-feeding genera that inhabit the mouth of their host, and whose variation in life-history strategies remains largely unexplored. Here we investigate the size relationship between the highly prevalent Ceratothoa italica and its main natural host, the striped sea bream, Lithognathus mormyrus. We found significant correlation between host size and that of both female and male parasites. Although the generality of a host–female size association in mouth-dwelling cymothoids had been widely recognised for some time, here we provide the first robust support for the occurrence of this size association also in mouth-dwelling male parasites. The potential underlying biological causes of the patterns are discussed, contributing to the debate on the evolution of host–parasite interactions, and the adaptive radiation of this family of parasitic isopods.

Partial characterization of superoxide dismutase activity in the Barber pole worm-Haemonchus contortus infecting Capra hircus and abomasal tissue extracts

ABSTRACT Objective To determine the activity of superoxide dismutase (SOD) in the male and female haematophagous caprine worms, Haemonchus contortus infecting Capra hircus, and their E/S products and also to analyse the effect of Haemonchus infection on the level of host SOD. Methods The SOD activity was analysed by using the pyrogallol autoxidation assay and non-denaturing polyacrylamide gel electrophoresis followed by specific enzyme staining by riboflavin-nitroblue tetrazolium method. Results The adult females were found to have higher enzyme activity than the male worms. Appreciable amount of SOD activity was also detected in the worm culture medium and female worms secreted more SOD in comparison to the male parasites. The SOD activity was negatively correlated to the worm burden. Statistically significant decrease in SOD activity ( P 0.05) was observed in the heavily infected host tissue in comparison to the control non-infected host tissue. SOD profile of the crude extracts of both the sexes revealed polymorphism and a fast migrating activity band being characteristic of E/S products. The SOD activities were found highly sensitive to potassium cyanide indicating the Cu/Zn form of SOD. Conclusions Haemonchus contortus is a key model parasite for drug and vaccine discovery. The presences of SOD activity in appreciable amount in the parasite as well as its E/S products indicate that it has a well-developed active antioxidant system to protect itself from the host immune attack. SOD could be the target for vaccine development which is the need of the hour as mass drug administration for parasite control has resulted in anthelmintic resistance across the globe and threatens the viability of sheep and goat industry in many regions of the world. The infection with Haemonchus causes a drastic reduction in SOD activity of the host tissue thus effecting its protective potential. One characteristic SOD band was found in the females which was not present in any other preparations and thus could be exploited for further studies on diagnostic/control measures.

Relationships of the branchial parasite Bopyrinella thorii (Isopoda, Bopyridae) and its host Thor floridanus (Decapoda, Hippolytidae)

Morphometric data are presented for developmental stages ofBopyrinellathorii(Richardson, 1904), obtained from 380 individuals ofThorfloridanusKingsley, 1878 infested by this parasite and collected by trawl net in Bahía de la Ascensión, Quintana Roo, Mexico. The close relationships between the sizes of host and parasite () and between sizes of the two sexes of the parasite () suggest the simultaneous growth of host and parasite and the permanence of the pairing of a male and female parasite throughout their lives. Cryptoniscus larvae ofB. thoriiwere sometimes attached intramuscularly to other body parts than the host’s gill chambers. Mature females unpaired with a male had ovarian activity visible through their exoskeleton, which reveals thatB. thoriicould produce oocytes even in the absence of a male. Bilateral double infestation, present in 4.2% of theT. floridanusspecimens analysed, was more frequent in smaller size classes of the host.

Transcriptome analysis of a parasitic clade V nematode: Comparative analysis of potential molecular anthelmintic targets in Cylicostephanus goldi

Clade V nematodes comprise several parasitic species that include the cyathostomins, primary helminth pathogens of horses. Next generation transcriptome datasets are available for eight parasitic clade V nematodes, although no equine parasites are included in this group. Here, we report next generation transcriptome sequencing analysis for the common cyathostomin species, Cylicostephanus goldi. A cDNA library was generated from RNA extracted from 17 C. goldi male and female adult parasites. Following sequencing using a 454 GS FLX pyrosequencer, a total of 475,215 sequencing reads were generated, which were assembled into 26,910 contigs. Using Gene Ontology and Kyoto Encyclopedia of Genes and Genomes databases, 27% of the transcriptome was annotated. Further in-depth analysis was carried out by comparing the C. goldi dataset with the next generation transcriptomes and genomes of other clade V nematodes, with the Oesophagostomum dentatum transcriptome and the Haemonchus contortus genome showing the highest levels of sequence identity with the cyathostomin dataset (45%). The C. goldi transcriptome was mined for genes associated with anthelmintic mode of action and/or resistance. Sequences encoding proteins previously associated with the three major anthelmintic classes used in horses were identified, with the exception of the P-glycoprotein group. Targeted resequencing of the glutamate gated chloride channel α4 subunit (glc-3), one of the primary targets of the macrocyclic lactone anthelmintics, was performed for several cyathostomin species. We believe this study reports the first transcriptome dataset for an equine helminth parasite, providing the opportunity for in-depth analysis of these important parasites at the molecular level. Sequences encoding enzymes involved in key processes and genes associated with levamisole/pyrantel and macrocyclic lactone resistance, in particular the glutamate gated chloride channels, were identified. This novel data will inform cyathostomin biology and anthelmintic resistance studies in future.

Phenotypic Dissection of a Plasmodium-Refractory Strain of Malaria Vector Anopheles stephensi: The Reduced Susceptibility to P. berghei and P. yoelii

Anopheline mosquitoes are the major vectors of human malaria. Parasite-mosquito interactions are a critical aspect of disease transmission and a potential target for malaria control. Current investigations into parasite-mosquito interactions frequently assume that genetically resistant and susceptible mosquitoes exist in nature. Therefore, comparisons between the Plasmodium susceptibility profiles of different mosquito species may contribute to a better understanding of vectorial capacity. Anopheles stephensi is an important malaria vector in central and southern Asia and is widely used as a laboratory model of parasite transmission due to its high susceptibility to Plasmodium infection. In the present study, we identified a rodent malaria-refractory strain of A. stephensi mysorensis (Ehime) by comparative study of infection susceptibility. A very low number of oocysts develop in Ehime mosquitoes infected with P. berghei and P. yoelii, as determined by evaluation of developed oocysts on the basal lamina. A stage-specific study revealed that this reduced susceptibility was due to the impaired formation of ookinetes of both Plasmodium species in the midgut lumen and incomplete crossing of the midgut epithelium. There were no apparent abnormalities in the exflagellation of male parasites in the ingested blood or the maturation of oocysts after the rounding up of the ookinetes. Overall, these results suggest that invasive-stage parasites are eliminated in both the midgut lumen and epithelium in Ehime mosquitoes by strain-specific factors that remain unknown. The refractory strain newly identified in this report would be an excellent study system for investigations into novel parasite-mosquito interactions in the mosquito midgut.

Transcriptional Responses of In Vivo Praziquantel Exposure in Schistosomes Identifies a Functional Role for Calcium Signalling Pathway Member CamKII

Treatment for clinical schistosomiasis has relied centrally on the broad spectrum anthelmintic praziquantel; however, there is limited information on its mode of action or the molecular response of the parasite. This paper presents a transcriptional and functional approach to defining the molecular responses of schistosomes to praziquantel. Differential gene expression in Schistosoma japonicum was investigated by transcriptome-wide microarray analysis of adult worms perfused from infected mice after 0.5 to 24 hours after oral administration of sub-lethal doses of praziquantel. Genes up-regulated initially in male parasites were associated with “Tegument/Muscle Repair” and “Lipid/Ion Regulation” functions and were followed by “Drug Resistance” and “Ion Regulation” associated genes. Prominent responses induced in female worms included up-regulation of “Ca2+ Regulation” and “Drug Resistance” genes and later by transcripts of “Detoxification” and “Pathogen Defense” mechanisms. A subset of highly over-expressed genes, with putative drug resistance/detoxification roles or Ca2+-dependant/modulatory functions, were validated by qPCR. The leading candidate among these was CamKII, a putative calcium/calmodulin-dependent protein kinase type II delta chain. RNA interference was employed to knockdown CamKII in S. japonicum to determine the role of CamKII in the response to praziquantel. After partial-knockdown, schistosomes were analysed using IC50 concentrations (50% worm motility) and quantitative monitoring of parasite movement. When CamKII transcription was reduced by 50–69% in S. japonicum, the subsequent effect of an IC50 dosage of praziquantel was exacerbated, reducing motility from 47% to 27% in female worms and from 61% to 23% in males. These observations indicated that CamKII mitigates the effects of praziquantel, probably through stabilising Ca2+ fluxes within parasite muscles and tegument. Together, these studies comprehensively charted transcriptional changes upon exposure to praziquantel and, notably, identified CamKII as potentially central to the, as yet undefined, mode of action of praziquantel.

Do Male and Female Cowbirds See Their World Differently? Implications for Sex Differences in the Sensory System of an Avian Brood Parasite

BackgroundMale and female avian brood parasites are subject to different selection pressures: males compete for mates but do not provide parental care or territories and only females locate hosts to lay eggs. This sex difference may affect brain architecture in some avian brood parasites, but relatively little is known about their sensory systems and behaviors used to obtain sensory information. Our goal was to study the visual resolution and visual information gathering behavior (i.e., scanning) of brown-headed cowbirds.Methodology/Principal FindingsWe measured the density of single cone photoreceptors, associated with chromatic vision, and double cone photoreceptors, associated with motion detection and achromatic vision. We also measured head movement rates, as indicators of visual information gathering behavior, when exposed to an object. We found that females had significantly lower density of single and double cones than males around the fovea and in the periphery of the retina. Additionally, females had significantly higher head-movement rates than males.ConclusionsOverall, we suggest that female cowbirds have lower chromatic and achromatic visual resolution than males (without sex differences in visual contrast perception). Females might compensate for the lower visual resolution by gazing alternatively with both foveae in quicker succession than males, increasing their head movement rates. However, other physiological factors may have influenced the behavioral differences observed. Our results bring up relevant questions about the sensory basis of sex differences in behavior. One possibility is that female and male cowbirds differentially allocate costly sensory resources, as a recent study found that females actually have greater auditory resolution than males.

Patterns of parasitism in insular lizards: effects of body size, condition and resource availability

The spatial distribution of a population of lizards is influenced by the distribution of resources and the individuals’ skills to gain access to them. On several Mediterranean islands with food scarcity and unpredictable resource availability, some resources can be extremely important during some periods of the year, as, e.g., the dead horse arum, Dracunculus muscivorus, on Aire Island, Spain. In this study, we analysed parasite infestation in an endemic lizard, Podarcis lilfordi, in relation to the distribution of D. muscivorus during spring. We found a higher prevalence of parasitism in males from a central area where the plant was significantly more abundant. Also, in this area, males were more abundant and larger than in two areas with lower plant densities. Moreover, overall differences appeared in the intensity of infection, which was higher in individuals from the central area, and we found a relationship between body size and parasite load, with more infected cells in larger individuals. Spatial distribution of individuals due to differential availabilities of D. muscivorus is proposed as an explanation for the observed differences.

Comparative profiling of microRNAs in male and female adults of Ascaris suum

Ascaris nematodes, which cause ascariasis in humans and pigs, are among the most important nematodes from both health and economic perspectives. microRNA (miRNA) is now recognized as key regulator of gene expression at posttranscription level. The public availability of the genome and transcripts of Ascaris suum provides powerful resources for the research of miRNA profiles of the parasite. Therefore, we investigated and compared the miRNA profiles of male and female adult A. suum using Solexa deep sequencing combined with bioinformatic analysis and stem-loop reverse transcription polymerase chain reaction. Deep sequencing of small RNAs yielded 11.71 and 11.72 million raw reads from male and female adults of A. suum, respectively. Analysis showed that the noncoding RNA of the two genders, including tRNA, rRNA, snRNA, and snoRNA, were similar. By mapping to the A. suum genome, we obtained 494 and 505 miRNA candidates from the female and male parasite, respectively, and 87 and 82 of miRNA candidates were consistent with A. suum miRNAs deposited in the miRBase database. Among the miRNA candidates, 154 were shared by the two genders, and 340 and 351 were female and male specific with their target numbers ranged from one to thousands, respectively. Functional prediction revealed a set of elongation factors, heat shock proteins, and growth factors from the targets of gender-specific miRNAs, which were essential for the development of the parasite. Moreover, major sperm protein and nematode sperm cell motility protein were found in targets of the male-specific miRNAs. Ovarian message protein was found in targets of the female-specific miRNAs. Enrichment analysis revealed significant differences among Gene Ontology terms of miRNA targets of the two genders, such as electron carrier and biological adhesion process. The regulating functions of gender-specific miRNAs was therefore not only related to the fundamental functions of cells but also were essential to the germ development of the parasite. The present study provides a framework for further research of Ascaris miRNAs, and consequently leads to the development of potential nucleotide vaccines against Ascaris of human and animal health significance.

Why are male malaria parasites in such a rush?

Disease-causing organisms are notorious for fast rates of molecular evolution and the ability to adapt rapidly to changes in their ecology. Sex plays a key role in evolution, and recent studies, in humans and other multicellular organisms, document that genes expressed principally or exclusively in males exhibit the fastest rates of adaptive evolution. However, despite the importance of sexual reproduction for many unicellular taxa, sex-biased gene expression and its evolutionary implications have been overlooked. We analyse genomic data from multiple malaria parasite (Plasmodium) species and proteomic data sets from different parasite life cycle stages. The accelerated evolution of male-biased genes has only been examined in multicellular taxa, but our analyses reveal that accelerated evolution in genes with male-specific expression is also a feature of unicellular organisms. This 'fast-male' evolution is adaptive and likely facilitated by the male-biased sex ratio of gametes in the mating pool. Furthermore, we propose that the exceptional rates of evolution we observe are driven by interactions between males and host immune responses. We reveal a novel form of host-parasite coevolution that enables parasites to evade host immune responses that negatively impact upon fertility. The identification of parasite genes with accelerated evolution has important implications for the identification of drug and vaccine targets. Specifically, vaccines targeting males will be more vulnerable to parasite evolution than those targeting females or both sexes.

Transcriptional Analysis of a Unique Set of Genes Involved in Schistosoma mansoni Female Reproductive Biology

Schistosomiasis affects more than 200 million people globally. The pathology of schistosome infections is due to chronic tissue inflammation and damage from immune generated granulomas surrounding parasite eggs trapped in host tissues. Schistosoma species are unique among trematode parasites because they are dioecious; females require paring with male parasites in order to attain reproductive maturity and produce viable eggs. Ex vivo cultured females lose the ability to produce viable eggs due to an involution of the vitellarium and loss of mature oocytes. In order to better understand schistosome reproductive biology we used data generated by serial analysis of gene expression (SAGE) to identify uncharacterized genes which have different transcript abundance in mature females, those that have been paired with males, and immature females obtained from unisexual infections. To characterize these genes we used bioinformatics, transcript localization, and transcriptional analysis during the regression of in vitro cultured females. Genes transcribed exclusively in mature females localize primarily in the vitellocytes and/or the ovary. Genes transcribed exclusively in females from single sex infections localize to vitellocytes and subtegumental cells. As female reproductive tissues regress, eggshell precursor proteins and genes involved in eggshell synthesis largely have decreased transcript abundance. However, some genes with elevated transcript abundance in mature adults have increased gene expression following regression indicating that the genes in this study function both in eggshell biology as well as vitellogenesis and maintenance of female reproductive tissues. In addition, we found that genes enriched in females from single sex infections have increased expression during regression in ex vivo females. By using these transcriptional analyses we can direct research to examine the areas of female biology that are both relevant to understanding the overall process of female development and worm pairing while determining novel therapeutic approaches directed at the maturation of female schistosomes.

The relative effect of parasites and social status on sperm traits in Arctic charr

Sperm production and sperm swimming speed, which most likely affect fertilization under sperm competition, are modified by proximate mechanisms. In a comprehensive observational study of free-living and reproductively active Arctic charr (Salvelinus alpinus), we examined the possible modulating effects of male social status (including ornamental development), parasite intensities, and immunity on novel traits indicative of ejaculate quality (e.g., Adenosine triphosphate (ATP) in sperm cells, levels of immunoglobulins attached to sperm cells, and the degree of DNA fragmentation in sperm cells). A multiple regression model showed no relationship between DNA fragmentation in sperm cells and abdominal coloration of charr, suggesting that sperm of colorful males are not better protected against oxidative stress. We found, however, that males with traits indicative of high social status had low amounts of ATP in sperm cells and also sperm cells with low swimming speed. Sperm production, on the other hand, was strongly predicted by parasite intensities only and these associations were mainly positive. Our results suggest that the presence of parasites seems to stimulate sperm production similar to what is observed among males entering subordinate reproductive roles. Thus, if resistance toward parasites is influencing parasite intensities, resistance may also indirectly be important for the “choice” of reproductive role and in turn investment in primary sex traits. Key wor ds: Arctic charr, immunity, parasite intensity, sexual selection, social status, sperm quality. [Behav Ecol]

The anthelmintic effect of plumbagin on Schistosoma mansoni

The anthelmintic effects of plumbagin (PB, 5-hydroxy-2-methyl-1,4-naphthoquinone) and praziquantel (PZQ) against adult Schistosoma mansoni in vitro were compared by estimating the relative motility (RM) values, survival indices (SI) and alterations of the tegument of flukes incubated in M-199 medium containing 1, 10 and 100 μg/ml of the drugs, at 1, 3, 6, 12 and 24 h. For the parasites incubated in 10 μg/ml, the RM values of the PB-treated group decreased at a more rapid rate than the PZQ-treated group. When incubated in 100 μg/ml all PB-treated flukes appeared immobile from 1 to 24 h when 91-100% died, while in the PZQ-treated group RM values were higher than that of PB and most flukes were still alive at 1-12 h, and at 24 h only 21% of flukes were killed. Furthermore, male parasites were more affected by PZQ than females as their RM values were significantly less than that of females at all doses. While in PB treatment, males and females showed less difference in response to the drug as their RM values were closer than those treated with PZQ. When observed by SEM, the tegument of untreated S. mansoni displayed no alteration, while in PB treated parasites it exhibited swelling, blebbing, loss of spines, disruption of tubercles and ridges, leading to erosion and lesion, exposure of the basal lamina, and sloughing of the tegument. PZQ induced similar tegumental changes as those observed in PB treatment but at longer incubation time and higher doses. These data indicated that PB had more anthelmintic effect on both sexes of adult S. mansoni than PZQ.

The Early Scope Gets the Worm, the Second Diagnosis

Purpose: A 69-year-old Bangladeshi male presented with abdominal pain and found to have microcytic anemia of 6.8 mg/dL (baseline 11) with low serum iron and ferritin. Stool for ova and parasites was negative. The patient denied any history of overt GI bleeding, change in stool caliber, family history of malignancy or weight loss. Chart review revealed a history of eosinophillia and prior colonoscopy significant for Trichuris trichiura (whipworm) but unclear if this was ever treated. Colonoscopy findings revealed multiple whipworms in the right colon. EGD was performed which revealed a friable, ulcerated pre-pyloric mass. Biopsies revealed moderately differentiated adenocarcinoma without H.pylori. Whipworm is endemic to tropical climates and patients are often infected by consuming larvae from soil-contaminated food or water. Patients are often asymptomatic until heavy worm burden. Patients with greater worm burden can present with symptomatic anemia, abdominal pain or diarrhea. Diagnosis is often made by identifying whipworm eggs in the stool, however this can be difficult when infection is caused by male parasites. The worm can invade the mucosa and produce mild inflammatory changes. Diagnosis of whipworm in the U.S. by colonoscopy is rare and only a few cases have been reported in the literature. The finding of gastric cancer was unexpected and demonstrates the role of discipline in completing the upper endoscopy as part of the iron deficiency anemia evaluation. In fact, helminth infection is thought to be protective for gastric cancer. A study of Columbian children suggested that the presence of helminth infection lowered the effect of H. pylori-associated gastric cancer by shifting the immune response from the pro-inflammatory Th1 to the more benign Th2 response.Figure: Ascending colon whipworm.Figure: Gastric ulcerated mass.

Seasonal dynamics of Thelandros maplestonei infections in the wall lizard, Hemidactylus flaviviridis in Imphal Valley, Manipur, India

The influence of seasons on the population dynamics of the nematode, Thelandros maplestonei infection in Hemidactylus flaviviridis was studied for one annual cycle in the Imphal Valley, Manipur, India. Various factors like the incidence, intensity, density, index of infection and dominance of this parasite was observed in relation to temperature and rainfall. The incidence, intensity, density, index of infection and dominance of T. maplestonei was higher in monsoon season, while lowest during winter. The intensity and density of female T. maplestonei was found to be comparatively higher than the male parasites and this observation indicated a shift from the previous studies. The study thus indicated that the temperature and rainfall acts as one of the most favourable extrinsic factors for T. maplestonei infections in H. flaviviridis in the Imphal Valley, Manipur.