Zoonotic Protozoan Research Articles

A review on current knowledge of major zoonotic protozoan diseases affecting farm and pet animals

Given the high importance of animal uses for human beings, avoidance of contact with animals is far from straightforward, even if there is a risk of zoonotic diseases. Animal products or byproducts are essential sources of food for humans. Also, there are large numbers of companion animals worldwide which are important for the soundness of mental health for the owners. Understanding of the disease in animals is of paramount importance to control and prevent transmission to humans. Zoonotic protozoan parasites, including malaria, babesiosis, trypanosomiasis, toxoplasmosis and cryptosporidiosis, can cause severe infections to humans, and some of them can drastically affect both economy and society. Impacts of such infections are aggravated when asymptomatic animals being in contact with susceptible individuals, including infants, pregnant women or immunocompromised people. Malaria, babesiosis and trypanosomiasis are vector-borne diseases that cause hemolytic anemia and high fever. Toxoplasmosis is a congenitally transmitted infection characterized by abortion and congenital abnormalities in infected persons and animals. Cryptosporidiosis is a highly contagious disease affecting humans and various animal species, and diarrhea is the main clinical form. These infections are globally distributed and affect various demographics. However, awareness of these often neglected diseases in almost all countries and communities is required to protect animals, owners, and customers. Thus, this review is aimed to provide the recent and current knowledge on transmission, epidemiology and control of some protozoan diseases of zoonotic importance.

Multilocus Genotyping of Giardia duodenalis Occurring in Korean Native Calves.

Giardia duodenalis is one of the most widely occurring zoonotic protozoan parasites causing diarrheal disease in calves. This study aimed to investigate the prevalence of G. duodenalis in Korean native calves and elucidate the causal factors associated with giardiasis in these animals. We investigated the sequences of three genes (ssu, bg, and gdh) of G. duodenalis in fecal samples collected from 792 Korean native calves during 2019–2020. Data were analyzed with regard to age, sex, sampling season, and the fecal sample type (based on its physical characteristics). The samples were screened for the three genes mentioned above, and 44 samples (5.6%) were G. duodenalis-positive. Polymerase chain reaction results showed a significantly higher prevalence of the infection in calves aged ≥1 month and in those with watery diarrhea in spring season. Screening for the gene sequences ssu (87.5%), bg (96.2%), and gdh (96.7%) revealed that most of the G. duodenalis-positive samples belonged to assemblage E. Four of the G. duodenalis-positive samples belonged to the zoonotic assemblage A. This study highlights the importance of continuous surveillance of genetic mutations in G. duodenalis for the detection of emerging variants of zoonotic G. duodenalis in calves.

Synthesis and evaluation of trypanocidal activity of derivatives of naturally occurring 2,5-diphenyloxazoles

African trypanosomiasis is a zoonotic protozoan disease affecting the nervous system. Various natural products reportedly exhibit trypanocidal activity. Naturally occurring 2,5-diphenyloxazoles present in Oxytropis lanata, and their derivatives, were synthesized. The trypanocidal activities of the synthesized compounds were evaluated against Trypanosoma brucei brucei, T. b. gambiense, T. b. rhodesiense, T. congolense, and T. evansi. Natural product 1 exhibited trypanocidal activity against all the species/subspecies of trypanosomes, exhibiting half-maximal inhibitory concentrations (IC50) of 1.1–13.5 μM. Modification of the oxazole core improved the trypanocidal activity. The 1,3,4-oxadiazole (7) and 2,4-diphenyloxazole (9) analogs exhibited potency superior to that of 1. However, these compounds exhibited cytotoxicity in Madin-Darby bovine kidney cells. The O-methylated analog of 1 (12) was non-cytotoxic and exhibited selective trypanocidal activity against T. congolense (IC50 = 0.78 µM). Structure-activity relationship studies of the 2,5-diphenyloxazole analogs revealed aspects of the molecular structure critical for maintaining selective trypanocidal activity against T. congolense.

Toxoplasma gondii Proteasome Subunit Alpha Type 1 with Chitosan: A Promising Alternative to Traditional Adjuvant.

As an important zoonotic protozoan, Toxoplasma gondii (T. gondii) has spread around the world, leading to infections in one-third of the population. There is still no effective vaccine or medicine against T. gondii, and recombinant antigens entrapped within nanospheres have benefits over traditional vaccines. In the present study, we first expressed and purified T. gondii proteasome subunit alpha type 1 (TgPSA1), then encapsulated the recombinant TgPSA1 (rTgPSA1) in chitosan nanospheres (CS nanospheres, rTgPSA1/CS nanospheres) and incomplete Freund’s adjuvant (IFA, rTgPSA1/IFA emulsion). Antigens entrapped in CS nanospheres reached an encapsulation efficiency of 67.39%, and rTgPSA1/CS nanospheres showed a more stable release profile compared to rTgPSA1/IFA emulsion in vitro. In vivo, Th1-biased cellular and humoral immune responses were induced in mice and chickens immunized with rTgPSA1/CS nanospheres and rTgPSA1/IFA emulsion, accompanied by promoted production of antibodies, IFN-γ, IL-4, and IL-17, and modulated production of IL-10. Immunization with rTgPSA1/CS nanospheres and rTgPSA1/IFA emulsion conferred significant protection, with prolonged survival time in mice and significantly decreased parasite burden in chickens. Furthermore, our results also indicate that rTgPSA1/CS nanospheres could be used as a substitute for rTgPSA1/IFA emulsion, with the optimal administration route being intramuscular in mass vaccination. Collectively, the results of this study indicate that rTgPSA1/CS nanospheres represent a promising vaccine to protect animals against acute toxoplasmosis.

Seroprevalence and Public Health Significance of Toxoplasmosis in Small Ruminants of Pastoral Community in Yabello District, Borana Zone, Southern Ethiopia.

Toxoplasmosis is a zoonotic protozoan disease. Data on seroepidemiology of toxoplasmosis in Ethiopia is scarce, almost null in the pastoral area of the Borana zone. The study was carried out to determine the seroprevalence, to identify risk factors of toxoplasmosis in sheep and goats, and to assess the awareness level of pastoralists about toxoplasmosis in the Yabello district of Borana zone, Southern Ethiopia. A cross-sectional study was conducted from November 2016 to April 2017 in six peasant associations of the Yabello district of Borana zone, Southern Ethiopia. A total of 400 serum samples of randomly selected small ruminants owned by pastoralists were examined to detect antibodies specific to Toxoplasma gondii using Latex Agglutination Test (SPINREACT, Girona, Spain). A semistructured questionnaire survey was used to conduct a face-to-face interview with owners (n = 100) of sampled flocks. Logistic regression analysis was used to determine the association of hypothesized risk factors. The overall seroprevalence was 52.8% of which 57.8 and 47.8% were sheep and goats, respectively. Univariate logistic regression analysis revealed a higher seroprevalence ratio of T. gondii infection in sheep than goats (COR: 1.95, 95% CI: 1.226–3.112; P = 0.005). Multivariate logistic regression analysis indicated significantly higher odds of acquiring T. gondii infection in adult animals (sheep: (AOR = 2.26, 95% CI: 1.323–3.874; P = 0.003), goats: (AOR = 2.15; 95% CI: 1.009–4.579; P = 0.047)), female sheep (AOR = 2.45; CI: 1.313–4.568; P = 0.005), animals from lowland areas (sheep: (AOR = 2.28; CI: 1.190–4.356; P = 0.013), goat: (AOR = 3.27; CI: 1.386–7.723; P = 0.007)), animal drinking lake water (sheep: (AOR = 1.93; CI: 1.011–3.698; P = 0.046), goat: (AOR = 2.96; CI: 1.297–6.771; P = 0.010)), and goats with history of abortion (AOR = 2.42; CI: 1.242–4.711; P = 0.009) than young animals, male (sheep), animals from midland areas, animals drinking wells water, and flock with no history of abortion (goat), respectively. Among respondents, 97.0% had no knowledge about toxoplasmosis and 75.0% drink raw milk and consume the meat of sheep and goats. 80.0% of respondents had no knowledge about the risk of cats to human and animal health while 70.0% of them had domestic cats and practice improper fetal body handling. Highly prevailing toxoplasmosis in small ruminants of the Yabello district might pose a serious economic loss and be a potential public health threat to the extremely vulnerable pastoralists. Therefore, awareness and further studies are warranted to tackle the economic and public health consequences of T. gondii infection.

Toxoplasma gondii prevalence in carnivorous wild birds in the eastern United States.

Toxoplasma gondii is an important zoonotic protozoan parasite that can infect all warm-blooded animals including mammals and birds. Raptors can be intermediate hosts for T. gondii and the infection may be dependent on their feeding habits. In this study, we investigated the seroprevalence of T. gondii in ten raptor species from Florida, Pennsylvania, and Tennessee followed by a parasite bioassay on select seropositive samples. From a total of 155 raptors, we detected T. gondii antibodies using a modified agglutination test (cutoff 1:25) in 32 (20.6%) birds. The T. gondii seroprevalence was 44.8% in Falconiformes (13/29), 75% in Strigiformes (15/20), and 3.8% in Ciconiiformes (4/106). All Ciconiiformes samples (hearts and sera) were collected from Pennsylvania during nuisance wildlife removal projects and all birds were apparently healthy. Falconiform and Strigiform samples were collected from an exotics clinic in Tennessee and a rehabilitation center in Florida. All sampled birds were dead or euthanatized due to failure of rehabilitation or treatment. There was no statistically significant difference in T. gondii seroprevalence between Tennessee and Florida in the tested raptors. There was also no statistically significant difference in T. gondii exposure between males and females or adults and subadults. Mice bioassay attempts using fresh brain and/or heart tissue were performed on four seropositive birds. We isolated viable T. gondii tachyzoites from one red-shouldered hawk (Buteo lineatus) and genotyped the isolate using polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP) of ten genetic markers. The isolated strain was designated as TgHawkFL1, which is ToxoDB PCR-RFLP genotype #28. Further research is needed to investigate the prevalence of T. gondii in raptors in the United States to obtain a better understanding of the life cycle, wildlife population impacts, and transmission dynamics of the parasite.

Serological and molecular evaluation of toxoplasmosis in patient undergoing chemotherapy for malignancies in southeast of Iran

Toxoplasma gondii is zoonotic protozoa that spread throughout the world. The aim of current study was determination of the prevalence of T. gondii infection in patient undergoing chemotherapy for malignancies using ELISA and two different molecular tests including Nested-PCR and LAMP techniques. This study was carried out in Ali Ibn Aboutaleb hospital in Zahedan cities, southeast of Iran. Totally, 154 serum samples from patient were test for detection of IgG and IgM antibodies against T. gondii by ELISA test. All of the samples were also test by Loop amplification (LAMP) and Nested-PCR with RE gene. Totally, 39.4% of the sample sera from cases were positive for IgG against T. gondii. After using RE-Nested-PCR technique, 29.8% sample sera were positively. After using LAMP technique, 33.1% of the samples were found to be positive. Based on our result, the RE-LAMP technique was more effective than RE-nested-PCR method in the detection of T. gondii DNA.

Prevalence and Some Predisposing Factors Associated with Cryptosporidium Infections in Domestic Poultry in Enugu State, Nigeria

Cryptosporidium is a zoonotic protozoan parasite that is of major public health and veterinary concerns. This study determined the prevalence and some predisposing factors associated with Cryptosporidium infection in domestic poultry kept in households and in the major live bird markets in the study area. Atotal of 314 fresh faecal samples were collected from domestic poultry in the randomly selected homes that keep poultry and live bird market in the study area. They were examined using the Formol-ether sedimentation method. Faecal smears were then stained by the Ziehl Neelson technique and examined under light microscopy. Cryptosporidium was identified using the staining characteristics of the oocysts. Results were analysed by descriptive statistics and GraphPad prism statistical package version 5.2.Cryptosporidium oocysts were detected in the faeces of 90 (28.7%) of the 314 poultry sampled. There was a strong association (p < 0.05) between the presence of Cryptosporidium oocysts and age, sex, breed and faecal consistency. However, there was no significant association (p > 0.05) between the presence of Cryptosporidium oocysts and locality as well as the type of management practice used in keeping the birds. This study suggests that domestic poultry in Enugu State harbour and shed Cryptosporidium oocysts in the environment. The shedding of this oocyst in the environment is of zoonotic importance especially in poultry that do not show clinical signs and therefore were not treated. Hence, constituting a public health risk, especially to immune-compromised humans, considering that almost every household keep chicken for food or income and the poultry dung is popularly used to cultivate vegetables eaten by humans and animals in the study area.
 Keywords: Cryptosporidium, Poultry, Prevalence, Risk Factor

Three Babesia species in Ixodes ricinus ticks from migratory birds in Sweden

BackgroundMigratory birds can cross geographical and environmental barriers and are thereby able to facilitate transmission of tick-borne pathogens both as carriers of infected ticks and as reservoirs of pathogenic microorganisms. Ixodes ricinus is one of the most abundant tick species in the Northern Hemisphere and a main vector of several Babesia species, some which pose a potential threat to human and animal health. At present only two cases of overt babesiosis in humans have so far been reported in Sweden. To better understand the potential role of birds as disseminators of zoonotic Babesia protozoan parasites, we investigated the presence of Babesia species in ticks removed from migratory birds.MethodsTicks were collected from birds captured at Ottenby Bird Observatory, south-eastern Sweden, from March to November 2009. Ticks were molecularly identified to species, and morphologically to developmental stage, and the presence of Babesia protozoan parasites was determined by real-time PCR.ResultsIn total, 4601 migratory birds of 65 species were examined for tick infestation. Ticks removed from these birds have previously been investigated for the presence of Borrelia bacteria and the tick-borne encephalitis virus. In the present study, a total of 1102 ticks were available for molecular analysis of Babesia protozoan parasites. We found that 2.4% of the ticks examined, all I. ricinus, were positive for mammal-associated Babesia species. Out of all Babesia-positive samples, Babesia venatorum was the most prevalent (58%) species, followed by Babesia microti (38%) and Babesia capreoli (4.0%). B. venatorum and B. capreoli were detected in I. ricinus larvae, whereas B. microti was only present in I. ricinus nymphs. This supports the view that the two first-mentioned species are vertically (transovarially) transmitted in the tick population, in contrast to B. microti. The largest number of Babesia-infected ticks was removed from the common redstart (Phoenicurus phoenicurus) and European robin (Erithacus rubecula).ConclusionsThis study reveals that Babesia protozoan parasites are present in ticks infesting migratory birds in south-eastern Sweden, which could potentially lead to the dissemination of these tick-borne microorganisms into new areas, thus posing a threat to humans and other mammals.Graphical

One Health Approach to Zoonotic Parasites: Molecular Detection of Intestinal Protozoans in an Urban Population of Norway Rats, Rattus norvegicus, in Barcelona, Spain.

Rattus norvegicus, the brown or Norway rat, is the most abundant mammal after humans in urban areas, where they live in close proximity to people. Among rodent-borne diseases, the reservoir role of Norway rats of zoonotic parasites in cities has practically been ignored. Considering the parasitic diseases in the One Health approach, we intended to identify and quantify the zoonotic intestinal protozoans (ZIP) in an urban population of R. norvegicus in the city of Barcelona, Spain. We studied the presence of ZIP in 100 rats trapped in parks (n = 15) as well as in the city’s sewage system (n = 85) in the winter of 2016/17. The protozoans were molecularly identified by means of a multiplex PCR (AllplexTM Gastrointestinal Panel-Parasite Assay). We also investigated the presence of co-infections among the species found. Four ZIP were identified, presenting significant prevalences in sewers, specifically Blastocystis (83.5%), Giardia duodenalis (37.7%), Cryptosporidium spp. (34.1%), and Dientamoeba fragilis (14.1%). Several co-infections among the detected ZIP were also detected. The reservoir role of ZIP that Norway rats play in cities as well as the role rats may play as sentinels of zoonotic parasites affecting humans in urban areas are strongly backed up by our findings. The increasing worldwide urbanization, climate change, and the COVID-19 pandemic are factors that are producing an increase in human–rat interactions. Our results should be considered a warning to the authorities to intensify rat control and surveillance in public health interventions.

Repeat-Driven Generation of Antigenic Diversity in a Major Human Pathogen,Trypanosoma cruzi.

Trypanosoma cruzi, a zoonotic kinetoplastid protozoan parasite, is the causative agent of American trypanosomiasis (Chagas disease). Having a very plastic, repetitive and complex genome, the parasite displays a highly diverse repertoire of surface molecules, with pivotal roles in cell invasion, immune evasion and pathogenesis. Before 2016, the complexity of the genomic regions containing these genes impaired the assembly of a genome at chromosomal level, making it impossible to study the structure and function of the several thousand repetitive genes encoding the surface molecules of the parasite. We here describe the genome assembly of the Sylvio X10/1 genome sequence, which since 2016 has been used as a reference genome sequence for T. cruzi clade I (TcI), produced using high coverage PacBio single-molecule sequencing. It was used to analyze deep Illumina sequence data from 34 T. cruzi TcI isolates and clones from different geographic locations, sample sources and clinical outcomes. Resolution of the surface molecule gene distribution showed the unusual duality in the organization of the parasite genome, a synteny of the core genomic region with related protozoa flanked by unique and highly plastic multigene family clusters encoding surface antigens. The presence of abundant interspersed retrotransposons in these multigene family clusters suggests that these elements are involved in a recombination mechanism for the generation of antigenic variation and evasion of the host immune response on these TcI strains. The comparative genomic analysis of the cohort of TcI strains revealed multiple cases of such recombination events involving surface molecule genes and has provided new insights into T. cruzi population structure.

Prevalence of infection by Cryptosporidium spp. in calves and associated risk factors in Northeastern Brazil

ABSTRACT Cryptosporidium spp. are zoonotic protozoa, frequently associated with diarrhea in calves, which are responsible for important economic losses. The aim of this study was to assess the prevalence of infection by Cryptosporidium spp. and its associated risk factors among calves raised in a milk production region of Northeastern Brazil. Fecal samples (n = 385) were obtained from young animals (up to ten months old) and evaluated by means of centrifugal fecal sedimentation in formalin-ether followed by the modified Ziehl-Neelsen staining technique. In addition, Odds Ratio (OR) was calculated to evaluate associations between variables and infection by these protozoa. Out of all samples analyzed, 25.7% (99/385) scored positive for the presence of Cryptosporidium spp. Contact with other species (goat and sheep) (OR = 3.33; p = 0.000), use of a semi-intensive rearing system (OR = 1.70; p = 0.024) and absence of hygienic conditions (fecal contamination of food and water) (OR = 1.64; p = 0.029) were considered to be risk factors. Data herein reported shows that the implementation of hygienic-sanitary measures on the farms studied, it is imperative to reduce Cryptosporidium spp. infection and consequently the economic impact caused by this pathogen.

Experimental infection with Toxoplasma gondii in broiler chickens (Gallus domesticus): seroconversion, tissue cyst distribution, and prophylaxis.

Toxoplasma gondii is a widespread zoonotic protozoan that infects most species of mammals and birds, including poultry. This study aimed to investigate the course of T. gondii infection and the efficacy of diclazuril and Artemisia annua in preventing infection in experimentally infected chickens. Seventy-five 1-month-old chickens, female and male, were randomly divided into five groups (n = 15 each) as follows: (1) uninfected untreated (negative control, NC); (2) infected with T. gondii genotype II/III isolated from a wild cat (group WC); (3) infected with T. gondii genotype II isolated from a domestic cat (group DC); (4) infected with T. gondii domestic cat strain and treated with the anticoccidial diclazuril (group DC-D); and (5) infected with T. gondii domestic cat strain and treated with the medicinal plant Artemisia annua (group DC-A). Clinical signs, body temperature, mortality rate, weight gain, feed conversion ratio, hematological parameters, and the presence of T. gondii-specific IgY antibodies were recorded in all groups. Five chickens per group were euthanized 28days post-infection (p.i.) and their brains, hearts, and breast muscle tested for T. gondii by mouse bioassay and polymerase chain reaction (PCR). No clinical signs related to the experimental infection were observed throughout the study period. T. gondii-specific antibodies were detected by day 28 p.i., but not in all infected chickens. Overall, T. gondii DNA was detected (bioassay or tissue digests) in all infected and untreated chickens (10/10), while viable parasite (bioassay) was isolated from 7 out of 10 chickens. The parasite was most frequently identified in the brain (7/10). There were no differences in the T. gondii strains regarding clinical infection and the rate of T. gondii detection in tissues. However, higher antibody titers were obtained in chickens infected with T. gondii WC strain (1:192) comparing with T. gondii DC strain (1:48). A. annua reduced replication of the parasite in 3 out of 5 chickens, while diclazuril did not. In conclusion, broiler chickens were resistant to clinical toxoplasmosis, irrespective of the strain (domestic or wild cat strain). The herb A. annua presented prophylactic efficacy by reduced parasite replication. However, further studies are required aiming at the efficacy of diclazuril and A. annua for the prevention of T. gondii infection in chickens using quantitative analysis methods.

Serologic Detection of <i>Toxoplasma gondii</i> in Cat Owners Residing at Dhaka Metropolitan Area of Bangladesh

Toxoplasma gondii is a zoonotic protozoan that can infect any warm-blooded mammal. T. gondii infects about one-third of the human population on the planet. Infection with the parasite in human causes toxoplasmosis that may pose a high risk in immunocompromised individuals under certain clinical conditions. Cats are the ultimate hosts of T. gondii where oocysts are formed through mating of male and female gametes. Infected cats can expel T. gondii oocysts in their feces, and thereby capable of pass on a disease to humans and other animals through consumption of foods, vegetables and water that are polluted with cat feces. The study was conducted to detect the presence of anti-T. gondii IgM and IgG antibodies in the blood of individuals with or without cat contact to determine if there is any relationship between cat contacts and T. gondii infection in humans. To address this, we enrolled subjects who contacted with the cat as target group and individuals with no cat contact as control group. Following register of different demographic data (including age, sex, education, foods habit, income status, etc.), whole blood from each enrolled subject of both the target group and control group was collected for serum preparation. T. gondii infected subjects were detected by Toxo Rapid test kit through identifying anti-T. gondii IgM and IgG antibodies in their serum. We found that only three out of twenty subjects who were in contact with cat showed positive IgG response while IgM antibody response was absent for all subjects. When compared with the data from control group, we did not find any significant association (p = 0.33) of cat contact with the transmission of T. gondii into human. However, with this small number of study subjects, we cannot conclusively say that there is no impact of cat contact on the transmission of T. gondii into human. Whether any association exists or not can be ascertained with a large number of subjects from different areas of Bangladesh in a future study in the population.

Diagnosis of Toxoplasmosis in Ruminants Aborted Fetuses in Northern Iran Using Molecular and Bioassay Techniques.

Background:Toxoplasma gondii is a zoonotic obligatory intracellular protozoan parasite that infects a wide range of warm-blooded species. This study aimed to obtain further information on the role of T. gondii infection in ruminant abortion (sheep, goats and cattle) using bioassay and PCR methods in Mazandaran province, northern Iran.Methods:Overall, 104 aborted fetuses (52 bovine, 48 ovine, 4 caprine) were collected at different stages of gestation during the lambing seasons in various parts of Mazandaran Province from Mar 2016 to May 2017. Brains of 104 aborted fetuses were bioassayed in female BALB/c mice. DNA was extracted from all brain samples using phenol-chloroform-isoamyl Alcohol instructions. RE gene was used for detection all of T. gondii DNA by conventional PCR assay.Results:The results of the bioassayed samples were negative because no tachyzoites or cyst were observed in the peritoneal and brain specimens of the mice. The detection of T. gondii DNA was confirmed by observation of a 529 bp band in 15 out of 104 fetuses (14.4%). The highest prevalence rate of T. gondii detected from sheep (16.6%) followed by cattle (13.4%) and goats (0%). The highest prevalence of the infection was observed in east area, while the lowest prevalence of the infection was observed in west area.Conclusion:T. gondii infection may partly be responsible for abortion and economic losses in livestock husbandry in this region. Therefore, further additional researches such as genotyping T. gondii and designing control strategies for improving management in livestock flocks are necessary.

Efficacy of Bifidobacterium animalis subsp. lactis BB-12 against Giardia duodenalis trophozoites: an experimental study

Giardia duodenalis, formerly known as Giardia lamblia, is an important zoonotic protozoan parasite. It mainly infects the intestines of humans, dogs, cats and domestic animals, causing diarrhea, abdominal pain, indigestion and weight loss. At present, all the clinical drugs for the treatment of Giardia have problems such as side effects and drug resistance to varying degrees, and the development of new drugs for the treatment of Giardia is still a hot issue. There is growing interest in using probiotics as an anti-intestinal parasite strategy. The present study aimed to assess the effect of supernatants of Bifidobacterium Animalis Subsp. lactis BB-12 on giardia the growth of giardia trophozoites. In this study, the Bifidobacterium animalis subsp. lactis BB-12 were cultured in BBL liquid medium, and the effects of the supernatants on the growth and adhesion of trophozoites of Giardia were observed. The results showed that the growth of Giardia flagellate was significantly inhibited by the supernatant. The influence of the supernatant on the morphology of the trophozoites was observed by microscope, and it was found that the surface of the trophozoites was uneven, the shape was atrophied, the surface cell membrane was broken to some extent, and the contents were spilt. In summary, the results of this study suggest that the fresh-cultured supernatants of the probiotic Bifidobacterium Animalis subsp. lactis BB-12 have anti-Giardia effects.

Cryptospordiosis: An infectious emerging protozoan zoonosis of public health significance

Zoonoses caused by diverse etiological agents, are important from public health and economic point of view, and are reported in humans and animals from developing and developed nations of the world. Cryptosporidiosis is an emerging food and waterborne zoonotic protozoan disease that has been detected in both human and animal populations all over the world. The source of infection is exogenous, and the ingestion of contaminated food and water is the principal mode of transmission. The oocysts of Cryptosporidium are abundant and pervasive in ambient water, where they can survive for months. It prefers epithelial cells found in the digestive tracts of a wide range of hosts. Waterborne transmission through drinking water or a swimming pool is common, resulting in outbreaks in several nations throughout the world. The disease can manifest itself in sporadic or epidemic forms. The infection has been recorded in immunocompetent and immunocompromised individuals. The watery diarrhea, abdominal cramps, nausea, anorexia and low grade fever are most commonly observed symptoms. The laboratory help is required to make an unequivocal diagnosis of disease. The preventive strategies include excellent hygienic measures to avoid the contamination of food and water by oocysts of Cryptosporidium. In addition, the role of veterinarian is highly imperative for the management of disease in domestic animals.

Awareness and habits of Nigerians towards toxoplasmosis and risk factors

Introduction: toxoplasmosis is a zoonotic protozoan disease caused by Toxoplasma gondii, which is a main cause of death related to foodborne diseases in the United States. In Nigeria, the prevalence of toxoplasmosis is 25.5% in food animals and 32% in humans. This study was designed to provide information on the awareness of toxoplasmosis and practices that expose people to the risk of the disease in Nigeria.

In Silico Identification and Functional Characterization of Conserved miRNAs in the Genome of Cryptosporidium parvum.

Cryptosporidium parvum, a predominant causal agent of a fatal zoonotic protozoan diarrhoeal disease called cryptosporidiosis, bears a worldwide public health concern for childhood mortality and poses a key threat to the dairy and water industries. MicroRNAs (miRNAs), small but powerful posttranscriptional gene silencing RNA molecules, regulate a variety of molecular, biological, and cellular processes in animals and plants. As to the present date, there is a paucity of information regarding miRNAs of C. parvum; hence, this study was used to identify miRNAs in the organism using a comprehensible expressed sequence tag–based homology search approach consisting of a series of computational screening process from the identification of putative miRNA candidates to the functional annotation of the important gene targets in C. parvum. The results revealed a conserved miRNA that targeted 487 genes in the model organism (Drosophila melanogaster) and 85 genes in C. parvum, of which 11 genes had direct involvements in several crucial virulence factors such as environmental oocyst protection, excystation, locomotion, adhesion, invasion, stress protection, intracellular growth, and survival. Besides, 20 genes showed their association with various major pathways dedicated for the ribosomal biosynthesis, DNA repair, transportation, protein production, gene expression, cell cycle, cell proliferation, development, immune response, differentiation, and nutrient metabolism of the organism in the host. Thus, this study provides a strong evidence of great impact of identified miRNA on the biology, virulence, and pathogenesis of C. parvum. Furthermore, the study suggests that the detected miRNA could be a potential epigenomic tool for controlling the protozoon through silencing those virulent and pathway-related target genes.

EFFECTS OF ALTERNATIVE NATURAL AND NANOTHERAPIES VERSUS METRONIDAZOLE ON GIARDIASIS INFECTED HAMSTERS

Giardia lamblia is one the most common human zoonotic protozoan affecting about 200 million peopleannually, but recurrent symptoms and drug resistance were reported in giardiasis patients. The presentstudy assessed the therapeutic effect of Tomex® and probiotics against giardiasis as well as evaluatedefficacy of chitosan nanoparticles and metronidazole. Sixty healthy male hamsters were dividedinto 6 groups. Each group consists of 10 hamsters as following: GI non-infected hamsters, GII infectedcontrol, GIII, GIV, GV & GVI infected with G. lamblia and treated with tomex, probiotics, chitosannanoparticles (CsNPs), and metronidazole (MTZ) respectively. Hamsters were orally infected with10,000 Giardia cysts. After 3 weeks stool samples were examined for Giardia samples and contentsfor intestinal histopathology and electron microscopy of Giardia trophozoite ultrastructure. The highestreduction in Giardia cyst and trophozoite were in hamsters received MTZ but with natural alternativetherapies chitosan nanoparticles showed a therapeutic effect with highest reduction in cyst andtrophozoite counts (80.59% & 76.55%) respectively and best recovery in intestinal pathology. MTZgave higher reduction rates (91.04% & 90.75%) respectively with normal intestinal histopathology.