A possible circulation of a dominant Dibothriocephalus nihonkaiensis haplotype in Japan revealed by molecular analysis of clinical tapeworm samples.

Human diphyllobothriasis, caused by Dibothriocephalus nihonkaiensis, is prevalent globally, especially in regions where raw fish is consumed. Recent molecular diagnostic techniques have made species identification of tapeworm parasites and the determination of genetic variations among parasite populations possible. However, only a few studies done over a decade ago, have reported on the genetic variation among D. nihonkaiensis in Japan. The present study employed PCR-based mitochondrial DNA analysis to specifically detect D. nihonkaiensis from archived clinical samples, and to determine any genetic variation that may exist among the Japanese broad tapeworms from patients of Kanagawa Prefecture, Japan. Target genes were amplified from DNA extracted from the ethanol- or formaldehyde-fixed samples by PCR. Further sequencing and comparative phylogenetic analyses based on mitochondrial COI and ND1 sequences were also performed. In our results, all PCR-amplified and sequenced samples were identified as D. nihonkaiensis. Analysis of COI sequences revealed two haplotype lineages. However, clustering of almost all COI (and ND1) sample sequences into one of the two haplotype clades, together with reference sequences from different countries worldwide, revealed a common haplotype among D. nihonkaiensis samples in our study. Our results suggest a possible presence of a dominant D. nihonkaiensis haplotype, with a global distribution circulating in Japan. Results from this study have the potential to improve the management of clinical cases and establish robust control measures to reduce the burden of human diphyllobothriasis in Japan.

RNA activation in ticks.

RNA activation (RNAa) is a burgeoning area of research in which double-stranded RNAs (dsRNAs) or small activating RNAs mediate the upregulation of specific genes by targeting the promoter sequence and/or AU-rich elements in the 3'- untranslated region (3'-UTR) of mRNA molecules. So far, studies on the phenomenon have been limited to mammals, plants, bacteria, Caenorhabditis elegans, and recently, Aedes aegypti. However, it is yet to be applied in other arthropods, including ticks, despite the ubiquitous presence of argonaute 2 protein, which is an indispensable requirement for the formation of RNA-induced transcriptional activation complex to enable a dsRNA-mediated gene activation. In this study, we demonstrated for the first time the possible presence of RNAa phenomenon in the tick vector, Haemaphysalis longicornis (Asian longhorned tick). We targeted the 3'-UTR of a novel endochitinase-like gene (HlemCHT) identified previously in H. longicornis eggs for dsRNA-mediated gene activation. Our results showed an increased gene expression in eggs of H. longicornis endochitinase-dsRNA-injected (dsHlemCHT) ticks on day-13 post-oviposition. Furthermore, we observed that eggs of dsHlemCHT ticks exhibited relatively early egg development and hatching, suggesting a dsRNA-mediated activation of the HlemCHT gene in the eggs. This is the first attempt to provide evidence of RNAa in ticks. Although further studies are required to elucidate the detailed mechanism by which RNAa occurs in ticks, the outcome of this study provides new opportunities for the use of RNAa as a gene overexpression tool in future studies on tick biology, to reduce the global burden of ticks and tick-borne diseases.

Food- and vector-borne parasitic zoonoses: Global burden and impacts.

Around 25% of the global population suffer from one or more parasitic infections, of which food- and vector-borne parasitic zoonotic diseases are a major concern. Additionally, zoonoses and communicable diseases, common to man and animals, are drawing increased attention worldwide. Significant changes in climatic conditions, cropping pattern, demography, food habits, increasing international travel, marketing and trade, deforestation, and urbanization play vital roles in the emergence and re-emergence of parasitic zoonoses. Although it is likely to be underestimated, the collective burden of food- and vector-borne parasitic diseases accounts for ∼60 million disability-adjusted life years (DALYs). Out of 20 neglected tropical diseases (NTDs) listed by the World Health Organization (WHO) and the Centres for Disease Control and Prevention (CDC), 13 diseases are of parasitic origin. There are about 200 zoonotic diseases of which the WHO listed eight as neglected zoonotic diseases (NZDs) in the year 2013. Out of these eight NZDs, four diseases, namely cysticercosis, hydatidosis, leishmaniasis, and trypanosomiasis, are caused by parasites. In this review, we discuss the global burden and impacts of food- and vector-borne zoonotic parasitic diseases.

Ambivalent Roles of Oxidative Stress in Triangular Relationships among Arthropod Vectors, Pathogens and Hosts.

Blood-feeding arthropods, particularly ticks and mosquitoes are considered the most important vectors of arthropod-borne diseases affecting humans and animals. While feeding on blood meals, arthropods are exposed to high levels of reactive oxygen species (ROS) since heme and other blood components can induce oxidative stress. Different ROS have important roles in interactions among the pathogens, vectors, and hosts. ROS influence various metabolic processes of the arthropods and some have detrimental effects. In this review, we investigate the various roles of ROS in these arthropods, including their innate immunity and the homeostasis of their microbiomes, that is, how ROS are utilized to maintain the balance between the natural microbiota and potential pathogens. We elucidate the mechanism of how ROS are utilized to fight off invading pathogens and how the arthropod-borne pathogens use the arthropods' antioxidant mechanism to defend against these ROS attacks and their possible impact on their vector potentials or their ability to acquire and transmit pathogens. In addition, we describe the possible roles of ROS in chemical insecticide/acaricide activity and/or in the development of resistance. Overall, this underscores the importance of the antioxidant system as a potential target for the control of arthropod and arthropod-borne pathogens.

Entomological Assessment of the Status and Risk of Mosquito-borne Arboviral Transmission in Ghana.

Entomological surveillance is one of the tools used in monitoring and controlling vector-borne diseases. However, the use of entomological surveillance for arboviral infection vector control is often dependent on finding infected individuals. Although this method may suffice in highly endemic areas, it is not as effective in controlling the spread of diseases in low endemic and non-endemic areas. In this study, we examined the efficiency of using entomological markers to assess the status and risk of arbovirus infection in Ghana, which is considered a non-endemic country, by combining mosquito surveillance with virus isolation and detection. This study reports the presence of cryptic species of mosquitoes in Ghana, demonstrating the need to combine morphological identification and molecular techniques in mosquito surveillance. Furthermore, although no medically important viruses were detected, the importance of insect-specific viruses in understanding virus evolution and arbovirus transmission is discussed. This study reports the first mutualistic relationship between dengue virus and the double-stranded RNA Aedes aegypti totivirus. Finally, this study discusses the complexity of the virome of Aedes and Culex mosquitoes and its implication for arbovirus transmission.

Oral activity of the antimalarial endoperoxide 6-(1,2,6,7-tetraoxaspiro[7.11]nonadec-4-yl)hexan-1-ol (N-251) against Leishmania donovani complex.

Visceral leishmaniasis (VL) is a major problem worldwide and causes significant morbidity and mortality. Existing drugs against VL have limitations, including their invasive means of administration long duration of treatment regimens. There are also concerns regarding increasing treatment relapses as well as the identification of resistant clinical strains with the use of miltefosine, the sole oral drug for VL. There is, therefore, an urgent need for new alternative oral drugs for VL. In the present study, we show the leishmanicidal effect of a novel, oral antimalarial endoperoxide N-251. In our In vitro studies, N-251 selectively and specifically killed Leishmania donovani D10 amastigotes with no accompanying toxicity toward the host cells. In addition, N-251 exhibited comparable activities against promastigotes of L. donovani D10, as well as other L. donovani complex parasites, suggesting a wide spectrum of activity. Furthermore, even after a progressive infection was established in mice, N-251 significantly eliminated amastigotes when administered orally. Finally, N-251 suppressed granuloma formation in mice liver through parasite death. These findings indicate the therapeutic effect of N-251 as an oral drug, hence suggest N-251 to be a promising lead compound for the development of a new oral chemotherapy against VL.

In vitro antiprotozoan activity and mechanisms of action of selected Ghanaian medicinal plants against Trypanosoma, Leishmania, and Plasmodium parasites.

Trypanosomiasis, leishmaniasis, and malaria are protozoan infections of public health importance with thousands of new cases recorded annually. Control of these infection(s) with existing chemotherapy is limited by drug toxicity, lengthy parenteral treatment, affordability, and/or the emergence of resistant strains. Medicinal plants on the other hand are used in the treatment of various infectious diseases although their chemical properties are not fully evaluated. In this study, we screened 112 crude extracts from 72 selected Ghanaian medicinal plants for anti-Trypanosoma, anti-Leishmania, and anti-Plasmodium activities in vitro and investigated their mechanisms of action. Twenty-three extracts from 20 plants showed significant antiprotozoan activity against at least 1 of 3 protozoan parasites screened with IC50 values less than 20 µg/ml. Eleven extracts showed high anti-Trypanosoma activity with Bidens pilosa whole plant and Morinda lucida leaf extracts recording the highest activities. Their IC50 (selectivity index [SI]) values were 5.51 µg/ml (35.00) and 5.96 µg/ml (13.09), respectively. Nine extracts had high anti-Leishmania activity with Annona senegalensis and Cassia alata leaf extracts as the most active. Their IC50 (SI) values were 10.8 µg/ml (1.50) and 10.1 µg/ml (0.37), respectively. Six extracts had high anti-Plasmodium activity with the leaf and stem-bark extracts of Terminalia ivorensis recording the highest activity. Their IC50 (SI) values were 7.26 µg/ml (129.36) and 17.45 µg/ml (17.17), respectively. Only M. lucida at 25 µg/ml induced significant apoptosis-like cell death in Trypanosoma parasites. Anti-Leishmania active extracts induced varying morphological changes in Leishmania parasites such as multiple nuclei and/or kinetoplast, incomplete flagella division, or nuclear fragmentation. Active extracts may be potential sources for developing new chemotherapy against these infections.

Indication of Risk of Mother-to-Child Toxoplasma gondii Transmission in the Greater Accra Region of Ghana.

Objectives Congenital infection with Toxoplasma gondii is known to result in neurological and brain disorders including ophthalmic disorders later in life. Research in Ghana revealed high sero-prevalence among pregnant women and eye patients. This study determines the risk of congenital transmission of T. gondii infection in Accra, Ghana. Methods One hundred consented pregnant women aged 18-45 years (mean 29.85 ± 5.76) participated. Venous blood and tissue samples were taken from the maternal side of each placenta after delivery. Cord blood samples were also taken after they were separated from the infants. Finger-prick blood was taken from infants of participating women at 2 or 6 weeks post-natal. ELISA was used to detect T. gondii antibodies in all blood samples while Nested-PCR was used to detect T. gondii DNA from placental tissues. Data was analysed using SPSS v. 16. Results Overall, 37.6 % of maternal blood, 39.5 % of umbilical cord blood, and 57.5 % of post-natal infant blood were positive for anti-T. gondii IgG. No anti-T. gondii IgM was detected in any of those samples. Toxoplasma gondii DNA was detected in 39.8 % of placental tissue samples. Strong association was observed in the occurrence of placental T. gondii DNA and anti-T. gondii IgG positive women (ø = 0.810, p < 0.00001) as well as high Relative risk shown in the likelihood of foetal exposure to infection in latently-infected women (RR 10.39; CI 4.47-24.17; p < 0.00001). Conclusions for Practice The presence of anti-T. gondii IgG antibodies only, and T. gondii DNA in placental tissues indicate the women might have been infected early during the pregnancy, placing about 39.8 % of the babies at risk. These results can strongly influence policy to screen and treat pregnant women for T. gondii infection.

Clonal types of Toxoplasma gondii among immune compromised and immune competent individuals in Accra, Ghana.

There are three major clonal lineages, types I, II, and III, of Toxoplasma gondii known to cause human toxoplasmosis worldwide. Toxoplasma gondii infections have, however, not been genotyped in Ghana. This study detected the clonal types infecting immune compromised and immune competent individuals in Accra, Ghana. Blood samples were obtained from 148 HIV seropositive pre-antiretroviral therapy individuals (0 ≤ CD4(+) T-cell count/µl blood ≤ 200) at the Fevers Unit and 149 HIV seronegative apparently healthy blood donors at the blood bank, all of the Korle-Bu Teaching Hospital. Genomic DNA was extracted and multilocus genotyping conducted by nested PCR-RFLP analysis using GRA6, SAG3, and BTUB gene markers. Among the HIV seropositive participants, 54.7% (81/148) were T. gondii DNA positive for any of the markers. Out of the 81, 42.0% (34) were positive for SAG3 only, 30.9% (25) for GRA6 only, 24.7% (20) for both SAG3 and GRA6, and 2.5% (2) for SAG3, GRA6, and BTUB. Overall, 93.8% of the positives were of clonal type II, 1.2% type I, while 4.9% (4) were atypical or mixed types (I and II). In the healthy blood donors, prevalence of T. gondii DNA positivity was 3.4% (5/149) by SAG3 and/or GRA6; among them, 60.0% (3/5) were type I, and the remaining 40.0%, type II. This study showed a relatively high prevalence of active T. gondii infections in immune compromised patients and low prevalence in immune competent individuals in Accra. Type II was highly prevalent. Detection of T. gondii in blood donors raises public health concerns and screening for T. gondii should be considered.

Congenital toxoplasmosis and pregnancy malaria detection post-partum: Effective diagnosis and its implication for efficient management of congenital infection.

Congenital toxoplasmosis (CT) and pregnancy malaria (PM) have been individually reported to cause severe negative outcomes in pregnancies but the diagnostic method is still debatable. This study sought to estimate the prevalence of PM and CT single and co-infections in pregnant women by using various specimens including plasma and placental tissues. Genomic DNA extracted from the placenta, cord blood or blood of mothers was tested by PCR. Conventional method of immunodiagnosis was done for CT. We tested 79 pregnant women aged 18-42 years (mean: 28±1.06). Prevalence of Plasmodium falciparum infection determined by PCR on mother's peripheral blood specimen was 6.3% whiles 57.3% was recorded for placental tissues (p<0.01). PCR testing for placental tissues showed 29.2% positive for Toxoplasma gondii, whiles 76.0% of mothers had serum IgG against T. gondii. It should be noted that 6.3% of the placental tissues showed PCR positive for SAG 3, a marker of active infection in T. gondii. Although there were no enhanced foetal disorders at birth in our study, there is a possibility of active transmission of T. gondii from mothers to foetuses even in immune mothers. Our study suggests that foetuses were exposed to P. falciparum and T. gondii in utero, and placenta is a better specimen for PCR in detecting such episodes. In cases of PCR-positive samples, clinical follow-up after birth may be important.