Effect of parasite egg size and quantity contrast of parasite-host eggs on recognition and rejection mode of Green-backed Tits

In the co-evolutionary system of avian brood parasitism,egg recognition and rejection are common and generally act as effective anti-parasitic adaptations by hosts.Accordingly,most studies have examined the role of parasite egg colors and markings in detection cues in hosts;however,studies focusing on the effects of egg size and quantity are relatively scarce and have mostly concentrated on the hosts of parasitic cowbirds.Here,we studied the egg recognition behaviors of a potential host of the Common Cuckoo(Cuculus canorus)—the Green-backed Tit(Parus monticolus),to determine:(1)whether the host uses the sizes of parasite eggs and/or the quantity contrast between parasite and host eggs as cues for recognition,(2)whether the host employs the template or discordant recognition mechanism for egg recognition,and(3)whether the size and quantity of parasite eggs affect the egg rejection modes of the hosts.The results indicate that Green-backed Tits did not use parasite egg size as a primary cue for egg recognition.We hypothesized that both visual and tactile detection might be involved in egg recognition by Green-backed Tits and suggest further studies after controlling for nest light conditions.Differences in egg quantity between parasites and hosts were not used as cues for egg recognition because the hosts employed the template mechanism rather than discordance to recognize parasite eggs.However,both the relative sizes and quantity of parasite and host eggs significantly affected the rejection modes of parasite eggs,and larger or more parasite eggs triggered higher probabilities of nest desertion in hosts.

Parasites of the liver:A global problem?

Parasitic liver diseases can be caused by trematodes,cestodes,nematodes,and protozoa.This pathology is significant because millions of people in different parts of the world have liver parasites,which can manifest themselves in the development of inflammation,liver cysts,cholecystitis,cholelithiasis,pancreatitis and liver cirrhosis that are often threatening their lives.The International Agency for Research on Cancer considers three species of trematodes,Schistosoma haematobium,Opisthorchis viverrini and Clonorchis sinensis,to be carcinogens.Complex modern examination methods,in some cases including extensive screening of large populations,are required for diagnosing liver parasites.Treatment of parasitic liver diseases is differentiated and can involve a combination of surgical and therapeutic measures.There is no doubt that the clinical and epidemiological scale allows one to regard parasitic liver diseases as a global healthcare problem.

Inter-species mRNA transfer among green peach aphids,dodder parasites,and cucumber host plants

mRNAs are transported within a plant through phloem.Aphids are phloem feeders and dodders(Cuscuta spp.)are parasites which establish phloem connections with host plants.When aphids feed on dodders,whether there is trafficking of mRNAs among aphids,dodders,and host plants and if aphid feeding a匚fects the mRNA transfer between dodders and hosts are unclear.We constructed a green peach aphid(GPA,Myzus persicae)-dodder(Cuscuta austra/is)-cucumber(Cucumis sativus)tritrophic system by infesting GPAs on C.australis,which parasitized cucumber hosts.We found that GPA feeding activated defense-related phytohormonal and transcriptomic responses in both C.australis and cucumbers and large numbers of mRNAs were found to be transferred between C.australis and cucumbers and between C.australis and GPAs;importantly,GPA feeding on C.australis greatly altered inter-species mobile mRNA profiles.Furthermore,three cucumber mRNAs and three GPA mRNAs could be respectively detected in GPAs and cucumbers.Moreover,our statistical analysis indicated that mRNAs with high abundances and long transcript lengths are likely to be mobile.This study reveals the existence of inter-species and even inter-kingdom mRNA movement among insects,parasitic plants,and parasite hosts,and suggests complex regulation of mRNA trafficking.

Coevolution of acoustical communication between obligate avian brood parasites and their hosts

The mutually antagonistic processes producing adaptations and counter-adaptations in avian brood parasites and their hosts provide a model system for the study of coevolution;this topic has long been an area of focus in ornithology and evolutionary biology.Although there is an extensive body of literature dealing with avian brood parasitism,few empirical studies have considered the effects of the coevolutionary processes associated with brood parasitism on the acoustic characteristics of parent–offspring communication.Under the strong selection pressures associated with brood parasitism,parasitic birds may,for instance,produce deceptive songs.The host may in turn evolve the ability to recognize these sounds as deceptive.At present,the mechanisms underlying the different competitive strategies employed by hosts and parasitic birds remain unclear.Here,we reviewed previous studies that investigated acoustic traits in scenarios of brood parasitism,highlighting possible adaptive functions.Using a meta-analysis,we identified no heterogeneity among studies of begging call adaptations in parasitic nestlings.However,our results may have been affected by the small number of applicable papers available for analysis.Our meta-analysis also suggested that studies of acoustic communication and transmission in adult hosts were highly heterogenous,suggesting that research methods were inconsistent among studies.Finally,we identified knowledge gaps and proposed several lines of future research.

Bi-Directional Regulation by Chinese Herbal Formulae to Host and Parasite for Multi-Drug Resistant <i>Staphylococcus aureus</i>in Humans and Rodents

A decline in the immunopotential of the host plays acritical factor(s) in the occurrence of infections with methicillin-resistant Staphylococcus aureus (MRSA) or microorganisms by opportunistic infection. In such an infection, no way out for therapeutic concept, therefore bi-directional trial was the final choice. So we selected aformula, Dang Gui Liu Huang Tang (dLHT), which could both augmentimmune factorsin host and exert bacteriostatic effect. We sought to break through the epidemic by MRSA especially in elderly patient, by the fundamental and clinical trial by employing minor TCM, characterizing bidirectional ability of the decoction by western methods. Animal Experiment: Mitomycin-C (MMC)-treated mice with or without the infection of MRSA were made. The experimental design was made up to examine the bacteriostatic action as well as the immunopo-tentiating bias of the promising Chinese herbal medicine, dLHT, which was first proved for its immune potentiating activities as well as their sensitivity to antibiotics, but not direct aseptic effect was clear for MRSA. Both basic and clinical data showed that this formula was effective on repelling from the infectious focus after the treatment of MRSA infection. After the administration of dLHT, the number of white blood cells in MMC-treated mice recovered to 80% of the normal level. In addition, the phagocytic activity of macrophages increased to 70% in the dLHT-treated group, while that of the non-treated group was only 20%. The bactericidal activity also recovered to the level close to the normal value by dLHT. The ratio of neutrophils in the dLHT-administered group increased to 2.2% (normal mice, 2.6%), whereas that in the non-terated group was only 0.5%. The bacterial count in the liver of MRSA-challenged mice reached the peak at six hours after the challenge in both dLHT-treated and non-treated mice. However, the number of bacteria in dLHT group was much greater than that in the non-treated group. The bacterial count in the blood showed an increase 12 and 24 hours after the challenge. Even 24 hours after the challenge, a significant number of bacteria existed in the blood of dLHT-administered group, whereas only a small number of bacteria detectable 6 hours after the challenge and the number gradually decreased thereafter in the dLHT-administered group. MRSA-challenged MMC-treated mice were treated by dLHT, vancomycin, or dLHT and vancomycin. All of non-treated mice died 8 days after the MRSA challenge, whereas the survival rates were 60% after dLHT treatment, 40% after vancomycin treatment, and 80% after dLHT and vancomycin treatment. All of MMC-treated mice, to which the phagocytic cells prepared from MMC-treated mice with dLHT administration had adoptively been transferred, survived from MRSA challenge. On the other hand, the survival rate of MMC-treated mice, to which the lymphocytes prepared from the same mice had adoptively been transferred, was 40%. Clinical Trial: All cases with dLHT treatment showed negative culture results for MRSA after the dLHT administration. The culture generally became negative less than 50 days after the initial administration, whereas one control case needed more than 100 days and the other was dead of the infection. One representative case, who was a 78-year-old woman suffering from hypertension, atrial fibrillation, and cerebral bleeding in the right occipital lobe, infected with MRSA during the antibiotic therapy for Streptococcus pneumoniae. The antibiotic therapy was halted and the dLHT administration started. Three weeks later, the culture result became negative. In addition, serum protein and albumin values also returned to the level that they had had before the infection of MRSA.

Host-parasite interactions in perpetual darkness:Macroparasite diversity in the cavefish Astyanax mexicanus

Astyanax mexicanus has repeatedly colonized cave environments,displaying evolutionary parallelisms in many troglobitic traits.Despite being a model system for the study of adaptation to life in perpetual darkness,the parasites that infect cavefish are practically unknown.In this study,we investigated the macroparasite communities in 18 cavefish populations from independent lineages and compared them with the parasite diversity found in their sister surface fish populations,with the aim of better understanding the role that parasites play in the colonization of new environments.Within the cavefish populations,we identified 13 parasite taxa,including a subset of 10 of the 27 parasite taxa known for the surface populations.Parasites infecting the cavefish belong to five taxonomic groups,including trematodes,monogeneans,nematodes,copepods,and acari.Monogeneans are the most dominant group,found in 14 caves.The macroparasites include species with direct life cycles and trophic transmission,including invasive species.Surprisingly,paired comparisons indicate higher parasite richness in the cavefish than in the surface fish.Spatial variation in parasite composition across the caves suggests historical and geographical contingencies in the host-parasite colonization process and potential evolution of local adaptations.This base-line data on parasite diversity in cavefish populations of A.mexicanus provides a foundation to explore the role of divergent parasite infections under contrasting ecological pressures(cave vs.surface environments)in the evolution of cave adaptive traits.

Patterns of host use by a precocial obligate brood parasite, the Black-headed Duck: ecological and evolutionary considerations

The Black-headed Duck (Heteronetta atricapilla) is unique among obligate avian brood parasites because its highly precocial young leave the host nest shortly after hatching and impose no post-hatching costs on their hosts. Accordingly, we might expect host-parasite interactions in this parasite to differ strikingly from those of other brood parasites — they should be able to parasitize a broad diversity of hosts and be highly successful with these hosts. We conducted the second detailed study ever completed on patterns of host use in Black-headed Ducks. Based on four years of systematic searches of multiple marshes in Argentina, we found no evidence that Black-headed Ducks ever had nests of their own, confirming the previous conclusion that Black-headed Ducks are, indeed, true obligate brood parasites. Contrary to expectation, however, we found that Heteronetta is ecologically dependent on a surprisingly small number of host species — two species of coots and a gull — all of which are widespread and locally abundant species. Other species are numerically less important as hosts either because they are relatively uncommon, or because they are avoided by the ducks. In the three main host species, hatching success of the duck eggs was also surprisingly low (≤ 28%), based on expectations for a precocial parasite, mainly due to host rejection or neglect. Mortality due to predation on host nests, in contrast, was low for all three primary host species. These observations corroborate Weller’s observations from a single-year study. The combination of a dependence on few primary hosts and a relatively low hatching success are inconsistent with some previous hypotheses for the evolution of obligate brood parasitism in Heteronetta. Instead, our observations, and those of Weller, suggest that intense nest predation in Austral wetlands, coupled with an abundance of a few common host species that aggressively defend their nests and obtain high nest success rates, may have been an important factor in the evolution of obligate parasitism in this enigmatic duck.

Egg discrimination by hosts and obligate brood parasites:a historical perspective and new synthesis

With the knowledge that cuckoos and cowbirds lay their eggs parasitically,and that some hosts eject parasitic eggs,ornithologists began to ponder the question of how host females discriminate between a foreign egg and their own eggs,wondering how hosts 'know' which egg to remove.Results of one of the rst uncontrolled experiments were inappropriately interpreted to imply ejection was based on discordancy,with hosts simply ejecting the egg in the minority,or the 'odd-looking' egg.Controlled experiments eventually revealed that hosts rst learn the appearance of own their eggs and discriminate between them and any odd egg in their nest,regardless of which egg type is in the minority.Recent work has shown that discordancy may play a role in discrimination by males mated successively with females that lay polymorphic eggs.We examine the details of the early experiments,in light of recent advances in studies of egg recognition.An ability to recognize eggs also has been extended,implicitly,to include obligate brood parasites,as it underlies several hypotheses in explanation of the behavior of parasites toward their hosts.Egg recognition in parasites,however,has not been experimentally con rmed,nor has a mechanism been identi ed by which parasites could discriminate between their own eggs and the other eggs in a nest.We review hypotheses(parasite competition,egg removal and multiple parasitism,ma a,farming) that require the ability of obligate brood parasites to discriminate eggs at di erent levels and the potential mechanisms used by parasites to recognize their own eggs and suggest experiments to test for egg discrimination.An assessment of the egg recognition ability of parasites is germane to our understanding of how parasites counteract defenses of hosts.

Diversity of parasitic cuckoos and their hosts in China

In this exposé we provide the first review of host use by brood parasitic cuckoos in a multiple-cuckoo system in China, based on our own long-term field data and a compilation of observations obtained from the literature. In total, we found that 11 species of cuckoos utilized altogether 55 host species. These hosts belong to 15 families, in which Sylviidae, Turdidae and Timaliidae account for 22.6%, 20.8% and 17.0% of parasitism records, respectively. The Common Cuckoo (Cuculus canorus) had the widest range of host species, accounting for 45.5% of the total number of parasitized species (25 in 10 families) of all parasitism records and is the most frequent brood parasite in the country. Cuckoo species differed in their egg coloration and the extent of egg polymorphism with most of them, e.g. the Common Cuckoo, the Lesser Cuckoo (C. poliocephalus) and the Plaintive Cuckoo (Cacomantis merulinus) laying well mimetic eggs with respect to their hosts based on human being’s visual observations, while others such as the Large Hawk-cuckoo (C. sparverioides), the Himalayan Cuckoo (C. saturatus) and the Asian Emerald Cuckoo (Chrysococcyx maculatus) usually laid non-mimetic eggs. The use of cuckoo hosts and egg color variation in China are compared with those in other parts of their ranges in Asia.

Host-Parasitoid系统的分岔与混沌控制

用数值模拟的方法,研究了Host-Parasitoid模型.该模型是一类非线性离散系统,反映了在一定的时间和空间内,寄生虫和寄宿主之间的生存状态.通过调节各种影响下的分岔参数,可以观察到系统具有周期泡,倍周期分叉,间歇混沌和Hopf分岔等复杂非线性动力学现象,揭示了系统通向混沌的途径.利用不同周期遍历下的奇怪吸引子和具有分形边界的吸引盆对系统的非线性特性进行了深入的探讨.最后利用参数开闭环控制法对系统的混沌状态进行了有效的控制.数值仿真和理论分析表明,选择相应的控制参数可将该系统的混沌状态控制到不同的稳定周期运动.

Geographic variation in parasitism rates of two sympatric cuckoo hosts in China

Rates of brood parasitism vary extensively among host species and populations of a single host species. In this study, we documented and compared parasitism rates of two sympatric hosts, the Oriental Reed Warbler （Acrocephalus orientalis） and the Reed Parrotbill （Paradoxornis heudei）, in three populations in China. We found that the Common Cuckoo （Cuculus canorus） is the only parasite using both the Oriental Reed Warbler and Reed Parrotbill as hosts, with a parasitism rate of 22.4%-34.3% and 0%-4.6%, respectively. The multiple parasitism rates were positively correlated with local parasitism rates across three geographic populations of Oriental Reed Warbler, which implies that higher pressure of parasitism lead to higher multiple parasitism rate. Furthermore, only one phenotype of cuckoo eggs was found in the nests of these two host species. Our results lead to two conclusions： （1） The Oriental Reed Warbler should be considered the major host of Common Cuckoo in our study sites; and （2） obligate parasitism on Oriental Reed Warbler by Common Cuckoo is specialized but flexible to some extent, i.e., using Reed Parrotbill as a secondary host. Further studies focusing on egg recognition and rejection behaviour of these two host species should be conducted to test our predictions.

Opportunistic and other intestinal parasites among HIV/AIDS patients attending Gambi higher clinic in Bahir Dar city,North West Ethiopia

Objective:To determine the magnitude of opportunistic and non-opportunistic intestinal parasitic infections among HTV/AIDS patients in Bahir Dar.Methods:Cross-sectional study was conducted among HIV/ AIDS patients attending Gambi higher clinic from Aprill- May 30,2009. Convenient sampling technique was employed to identify the study subjects and hence a total of 248 subjects were included.A pre-tested structured questionnaire was used to collect sociodemographic data of patients.Stool samples were examined by direct saline,iodine wet mount, formol-ether sedimentation concentration and modified Ziehl-Neelsen staining technique. Results:Out of 248 enrolled in the study,171(69.0%)(90 males and 81 females) were infected with one or more intestinal parasites.The highest rate of intestinal parasites were observed among HIV/AIDS patients(80.3%,151/188),and the infection rate of HIV negative individuals was 33.3%(20/60).Cryptosporidum parvum(43.6%),Isospora belli(15.5%) and Blastocystis hominis (10.5%) were opportunistic parasites that were found only in HIV/AIDS patients.Conclusions: Opportunistic parasite infections are common health problem among HIV/ AIDS patients in the study area.Therefore,early detection and treatment of these parasites are important to improve the quality of life of HIV/AIDS patients.

Molecular basis for identification of species/isolates of gastrointestinal nematode parasites

Gastrointestinal（GI） parasitism is the most serious constraint throughout the world in small ruminants which causes significant production loss in animals.GI parasites are major contributor to reduce productivity in terms of meat,milk and wool in animals.Control of GI parasite is done primarily by anthelmintic treatment where choice and schedule of treatment is done after identification and quantitation of individual parasite.Identification of GI parasites is done through microscopic method by identifying specific morphological characteristics of egg and larva（L3）.Since most of parasite eggs are having similar morphological characteristics, identification up to species level through microscopy is not possible in most of cases.To address this issue,molecular techniques are the viable alternative for identification of species as well as molecular level differences within a species（isolates） of parasites.Different DNA based molecular techniques viz.PCR,AFLP,RAPD,RFLP,PCR-SSCP,real time PCR,DNA microarray etc.have been used for identification and to assess the genetic diversity among parasite population.For identification of species,the characteristic sequence of genomic DNA of different species should differ to allow the delineation of species,but at the same time,no/minor variation within the species should exist.In contrast,for purpose of identifying population variants（strains/isolates）, a considerable degree of variation in the sequence should exist within a species.Various target regions,including nuclear ribosomal DNA（rDNA）,mitochondrial DNA（mtDNA） or repetitive DNA elements（microsatellite loci）,which show considerable variation in the number of repeats within individuals have been employed to achieve the identification of parasites species or strain.

Malaria parasite carbonic anhydrase:inhibition of aromatic/heterocyclic sulfonamides and its therapeutic potential

Plasmodium falciparum(P.falciparum) is responsible for the majority of life-threatening cases of human malaria,causing 1.5-2.7 million annual deaths.The global emergence of drug-resistant malaria parasites necessitates identification and characterisation of novel drug targets and their potential inhibitors.We identified the carbonic anhydrase(CA) genes in P.falciparum.The pfGA gene encodes an α-carbonic anhydrase,a Zn^(2+)-metalloenzme,possessing catalytic properties distinct from that of the human host CA enzyme.The amino acid sequence of the pfCA enzyme is different from the analogous protozoan and human enzymes.A library of aromatic/heterocyclic sulfonamides possessing a large diversity of scaffolds were found to be very good inhibitors for the malarial enzyme at moderate-low micromolar and submicromolar inhibitions.The structure of the groups substituting the aromatic-ureido-or aromatic-azomethine fragment of the molecule and the length of the parent sulfonamide were critical parameters for the inhibitory properties of the sulfonamides.One derivative,that is,4-(3,4-dichlorophenylureido)thioureidobcnzcnesulfonamide(compound 10) was the most effective in vitro Plasmodium falciparum CA inhibitor,and was also the most effective antimalarial compound on the in vitro P.falciparum growth inhibition.The compound 10 was also effective in vivo antimalarial agent in mice infected with Plasmodium berghei,an animal model of drug testing for human malaria infection. It is therefore concluded that the sulphonamide inhibitors targeting the parasite CA may have potential for the development of novel therapies against human malaria.

Survey on gastrointestinal parasites and detection of Cryptosporidium spp. on cattle in West Java,Indonesia

Objective:To evaluate the presence of gastrointestinal parasites on cattle in Indonesia because the prevalence of parasites varies between counlries depending on the terrain surrounding livestock farms and investigations in Indonesia have never been performed.Methods:Fecal samples from cattle at 35 farms in 7 districts in West Java,Indonesia,has been examined using the floatation or sedimentation methods,and a immunofluorescence assay and experimentally inoculation to mice for Cryptosporidium or Giardia spp.Results:153 of 394 examined cattle(38.8%)were infected with gastrointestinal parasites.The prevalence of Eimeria spp.,Nematoda spp.(including Oesophagustomum and Bunostomum-like),Fasciola gigantica and Paramphistomum spp.was 22.4%,11.2%,12.5%and 3.8%,respectively.Cryptosporidium andersoni(C.andersoni)was also found in two samples.One isolate of this parasite was confirmed to be transmitted to mice,in contrast to the isolates from other countries.Conclusions:although this survey is preliminary,the results shows that the infection of gastrointestinal parasites in Indonesia was not high,but these infected cattle could be as a potential source leading to economic losses in livestock production.

Oomycetes and fungi:important parasites on marine algae

Considering that the field is largely unexplored and its importance to aquaculture,outline of oomycetes and fungi parasiting on marine algae was provided in this paper,including 15 species of oomycetes,six species of chytrids,31 Ascomycota species and one species of mitosporic fungi.In natrue,both the oomycetes and chytrids frequently occurred and induced prevalences of disease which could destroy the populations of host plants greatly.However,the parasites in Ascomycota on algae have never occurred as epidemics so far.Some issues relating to the field were discussed such as performing tests to satisfy Koch＇s postulates,investigations of host specificity,interactions between host and parasite and the potential effects of environmental factors on occurrence of a disease,which are urgent in need of further investigations.

Temporal-spatial patterns of intestinal parasites of the Hooded Crane(Grus monacha) wintering in lakes of the middle and lower Yangtze River floodplain

Background: Parasites have adverse effects on the life and survival of many migratory waterbirds, especially birds on the endangered species list. Hooded Cranes are large migratory colonial waterbirds wintering in wetlands,which are prone to parasite infection, thus monitoring the diversity of parasites is important for sound wetland management and protection of this species.Methods: From November 2012 to April 2013, we collected 821 fresh faecal samples from the three lakes(Poyang,Caizi and Shengjin Lake) in the lower and middle Yangtze River floodplain, and detected with saturated brine floating and centrifugal sedimentation methods. Parasite eggs were quantified with a modified Mc Master's counting method.Results: In this study, 11 species of parasites were discovered, i.e., two coccidium(Eimeria gruis, E. reichenowi), five nematodes(Capillaria sp., Strongyloides sp., Ascaridia sp., Trichostrongylus sp., Ancylostomatidae), three trematodes(Echinostoma sp., Echinochasmus sp., Fasciolopsis sp.) and one cestode(Hymenolepis sp.). About 57.7% of the faecal samples showed parasitic infection. All species of parasites were found at the three sites except Hymenolepis which was not found at Poyang Lake. While most samples were affected by only one or two species of parasites, infection by Eimeria spp. was the most common(53.1%). From One-Way ANOVA analysis of the three lakes, parasite species richness index(p = 0.656), diversity index(p = 0.598) and evenness index(p = 0.612) showed no significant difference. According to the statistical analysis of our data, there were no significant difference in parasite species richness index(p = 0.678) and evenness index(p = 0.238) between wintering periods, but a strong difference in diversity index(p < 0.05).Conclusions: Our study suggests that in the wintering Hooded Crane populations, parasite diversity is more sensitive to changes in the overwintering periods than to locations. This also indicates that with the limitations of migration distance, the parasites may not form the differentiation in Hooded Crane populations of the three lakes.

Tissue tropism and parasite burden of Toxoplasma gondii RH strain in experimentally infected mice

Objective:To evaluate parasite distribution and tissue tropism of Toxoplasma gondii tachyzoites in experimentally infected mice using real time QPCR.Methods:In this survey 16 Balb/c mice were inoculated with 1×10~4 alive tachyzoites of Toxoplasma gondii RH strain.After 1,2,3 days post infection and the last day(before death),different tissues of mice including blood,brain,eye,liver,spleen,kidney,heart and muscle were harvested.Following tissues DNA extraction,the parasite burden was quantified using real time QPCR targeting the B1 gene(451 bp).Results:It showed that Toxoplasma after intraperitoneal injection was able to movement to various tissues in24 hours.Parasite burden was high in all tissues but the most number of parasites were observed in kidney,heart and liver,respectively.Conclusions:These data provide significant baseline information about Toxoplasma pathogenesis,vaccine monitoring and drug efficiency.

Prevalence of intestinal parasite infections among patients in local public hospitals of Hail,Northwestern Saudi Arabia

Objective:To evaluate the prevalence of intestinal parasites among patients in Hail,Northwestern Saudi Arabia.Methods:Stool samples were collected from 130 patients(69females and 61 males) in Hail General Hospital.Each sample was examined by direct wet mount microscopic examination using both normal saline and Lugol's iodine preparation and concentration techniques using salt and formol-ether solutions.Permanent stained smears were performed for intestinal coccidian using modified Ziehl-Neelsen technique.Results:The overall prevalence of intestinal parasitic infection was 45.38%(59 cases).Forty-four(33.84%)were found to be infected with one or more intestinal protozoa.5(3.84%) were infected with helminthes and 10(7.69%) had mixed infection with both helminthes and protozoa.The most common intestinal helminth detected was Ancyloxtoma duvdenale(n=5.3.84%),followed by Ascaris lumlmcnidex.Taenia sp.and Trichuris trichiura(n=2 for each species,1.5%).For intestinal protozoa,the coccidian Cryptosporidium parvum(n=25,19.23%) was the most common followed by Entamoeba histolytica/dispur(n=21,16.15%),Giurdia lamblia(n=15,11.54%),Entamoeba coli(n=5.3.85%) and Blastocysts hominis(n=3,2.30%).The prevalence of intestinal parasitic infections in females was significantly higher than in males(P<0.05).Conclusions:This is the first study highlighting that intestinal parasites are still an important public health problem in Northwestern Saudi Arabia Therefore,health education would be the best way to prevent from intestinal parasite infections which are mainly food borne diseases.

Impact of hygienic level on parasite infection

Objective:To find out the prevalence of intestinal parasites among primary school population(the most vulnerable group) in rural and urban areas in south Jordan.Methods:During a medical civic action in the south of Jordan in summer 2000,stool specimens were collected from 2400 primary school children,aged from 6-12 years,and examined for the detection of intestinal parasitic infection from both urban(1 100 samples) and rural(1 300 samples) areas in south Jordan.Results:The results indicated that the overall prevalence of intestinal parasitic infection was 28.5%.It was more in rural(33.2%) than in urban(23.0%) areas,but no sex difference was found.As regard to the type of infection,Giardia lamblia was the commonest intestinal protozoa, with a rate of 42.6%,while Enterobious vermicularis was the commonest helminth recorded in our study with a rate of 5.9%.Conclusions:Health education by health and school authorities is recommended,particular attention should be paid to repairing the sewage disposal system as well as water supply,which acts as main source of water pollution.