Periodicity in the Quantity and Ratio of Pheromone Components in Volatile Emissions from Virgin Females of the Spotted Stalk Borer Moth Chilo partellus (Swinhoe)

Volatile sex pheromone was collected from the extruded pheromone gland of females of the spotted stalk borer moth Chilo partellus and trapped on glass wool. The pheromone was collected from females on the night of eclosion, 1st, 2nd, 3rd and 5th scotophases thereafter. The female sex pheromone components, (Z)-11-hexadecenal and (Z)-11-hexadecen-1-ol were identified by gas chromatography co-injection with synthetic authentic compounds and confirmed by GC-mass spectrometry. The quantity of the pheromone components was determined by comparison of GC peak areas with that of (E,Z)-3,13-octadecadienyl acetate as an internal standard. Periodicity in the pheromone emission was uni-modal with a peak about the 7-10 h into the scotophase. During the peak period, (Z)-11-hexadecenal was emitted at a rate of 43.1, 30.9, 21.5 and 16.5 ng/30 min on the day of eclosion, 1st, 3rd and 5th scotophases, respectively. A marked reduction in the release rate of the pheromone components was recorded with progressing age of females. This decrease was faster for (Z)-11-hexadecen-I-ol than for (Z)-11-hexadecenal which resulted in a spectacular shift in the ratio (Z)-11-hexadecen-I-ol ranging from about 1:1 at eclosion to 9:1, 22:1 and 32:1 in the 1st, 3rd and 5th scotophases, respectively. The age-dependent shift in both release rate and ratio of pheromone components corresponds to the change in attractiveness of females to mate-searching males. The periodicity in the quantity and blend ratios of C. partellus pheromone is discussed in light of development of a pheromone-based bait for the management of this pest. Key words: Periodicity, Lepidoptera, Pyralidae, Chilo partellus, sex pheromone, pheromone East and Central African Journal of Pharmaceutical Sciences Vol.6(2) 2003: 36-4

Molluscicidal Activity of Selected Plant Extracts against Adult and Juvenile Biomphalaria Pfeifferi

Human Schistosomiasis is a debilitating infection whose transmission depends solely on the presence of snail intermediate hosts. It is a major public health problem second only to malaria in terms of morbidity and mortality and predominant in tropical and subtropical countries. Globally, over 240 million people are infected and close to 600milion are at risk.Strategies for Control of Schistosomiasis include; Chemotherapy with praziquantel, mollusciciding with Niclosamide, health education, community participation, provision of clean water and improved sanitation. Chemotherapy and use of synthetic molluscicides faces serious drawbacks of being costly, poses negative impact on environment and development of resistant strains of intermediate host snails and parasites. Plant extracts that are effective against host snails and non-toxic to non-target organisms could provide an alternative molluscicide to the current Niclosamide.This study evaluated molluscicidal activity of aqueous and methanol extracts against juvenile and adult Biomphalaria pfeifferi in vitro.Assesment of snail susceptibility to extracts was done by immersion method in accordance to WHO protocal.10 adult and juvenile snails were exposed separately to serial dilutions of 10, 20, 50, 100 and 150ppm (mg/l) of both aqueous and methanol extracts for 48 hours. Mean mortality of snails was subjected to probit analysis to determine the lethal dose (LD50) that killed 50% of the snails. The most active extracts on both juvenile and adults were Phytolacca dodecandra (LD50 8.78 and 12.58ppm) and Solannum linaeanum (LD50 16.81 and 23.25ppm) respectively.This was followed by Solanum americanum (LD50 36.17 and 38.00ppm) and Annona squamosa (LD50 51.96 and 59.00ppm) respectively. The least active extracts were Piper nigrum (LD50 74.13 and 89.95ppm) and Rhizophora mucranata LD50 94.56 and 109.82 ppm) respectively. Average mortality of Phytolacca dodecandra and solanum linaeanum was significantly similar (p ˃ 0.05) to that of niclosamide the currently used molluscicde.Since a good molluscicide should kill snails at a concentration of 100ppm or lower, this study demonstrated potency of four plant species from Kenya with molluscicidal activity against the intermediate hosts of Schistosoma mansoni. Keywords: Schistosomiasis, Biomphalaria pfeifferi, Schistosoma mansoni, Molluscicide, Phytolacca dodecandra, Solanum linaeanum, Solanum americanum, Annona squamosa

Evaluation of Cercaricidal and Miracicidal Activity of Selected Plant Extracts Against Larval Stages of Schistosoma Mansoni

Schistosomiasis is a parasitic disease caused by blood-flukes of the genus Schistosoma. It is one of the most widespread of all human parasitic diseases, ranking second only to malaria in terms of its socioeconomic and public health importance in tropical and subtropical areas.More than 207 million people, 85% of whom live in Africa, are infected with schistosomiasis,and an estimated700 million people are at risk of infection in 76 countries.Control of schistosomiasis faces serious drawbacks of emergence of drug resistant parasites and molluscicide resistant snail hosts.Due to improper waste disposal,infected faecal matter enter water bodies such as canals rivers and springs where miracidia that hatch from parasite eggs  develop into cercariae inside snail intermediate hosts and are infective to humans upon release in to the water.This study sought to evaluate the miracicidal and cercaricidal activity of selected plant extracts on larval stages of Schistosoma mansoni.Ten cercariae and miracidia were exposed to extract concentrations ranging from 10-150ppm.The most active extracts were Phytolacca dodecandra (LT50 10.84 and16.91minutes) and Solanum linaeanum (LT50 of 22.86 and 26.96 minutes) respectively that killed 50% of miracidia and cercariae in less than 30minutes.This was followed closely by Solanum americanum (LT50 31.02 and 31.89) and Anonna squamosa LT50 35.29 and 40.46minutes respectively.Piper nigrum was the least active recording LT50 46.84 and 56.75 of miracidia and cercaria respectively.Miracidia were more susceptible to extracts than cercariae.The higher susceptibility of miracidia to extracts has also been reported in other studies and it is advantageous since killing one miracidium prevents the formation of thousands of cercariae which are infective to humans.All the extracts killed larvae within one hour at concentration less than 100ppm and could be categorized as potent cercaricide and miracicides. Keywords: Miracidal, Cercaricidal,Schistosomiasis,Phytolacca dodecandra,Solanum linaeanum,Solanum americanum,Anonna squamosa and Piper nigru

Bacterial diversity in the intestinal tract of the funguscultivating termite Macrotermes michaelseni (Sjöstedt)

Microorganisms in the intestinal tracts of termites play a crucial role in the nutritional physiology of termites. The bacterial diversity in the fungus-cultivating Macrotermes michaelseni was examined usingboth molecular and culture dependent methods. Total DNA was extracted from the gut of the termite and 16S rRNA genes were amplified using bacterial specific primers. Representatives from forty-one (41) RFLP patterns from a total of one hundred and two (102) clones were sequenced. Most of the clones were affiliated with 3 main groups of the domain Bacteria: Cytophaga-Flexibacter-Bacteriodes(73), Proteobacteria (13), and the low G+C content Gram-positive bacteria (9). Two RFLPs related to planctomycetes, but deeper branching than known members of the phylum, were detected. In addition, 1 and 2 RFLPs represented the spirochetes and TM7-OP11 groups, respectively. In studies using culture dependent techniques, most of the isolates obtained belonged to the Gram-positive bacteriawith a high G+C content. However, only one of the clones represented Gram-positive bacteria with High G+C content. These results show a high bacterial diversity in the intestinal microbiota of M. michaelseni, which continues to escape cultivation. As is the case in other termites many of the clones represent previously uncultured bacteria. The fact that most of the clones clustered with clones from Macrotermes gilvus provides further support for the hypothesis that microorganisms in intestinal tracts of termites have co-evolved with their hosts

Seroprevalence and Risk Factors of Inkoo Virus in Northern Sweden

The mosquito-borne Inkoo virus (INKV) is a member of the California serogroup in the family Bunyaviridae, genus Orthobunyavirus. These viruses are associated with fever and encephalitis, although INKV infections are not usually reported and the incidence is largely unknown. The aim of the study was to determine the prevalence of anti-INKV antibodies and associated risk factors in humans living in northern Sweden. Seroprevalence was investigated using the World Health Organization Monitoring of Trends and Determinants in Cardiovascular Disease study, where a randomly selected population aged between 25 and 74 years (N = 1,607) was invited to participate. The presence of anti-INKV IgG antibodies was determined by immunofluorescence assay. Seropositivity for anti-INKV was significantly higher in men (46.9%) than in women (34.8%; P <0.001). In women, but not in men, the prevalence increased somewhat with age (P = 0.06). The peak in seropositivity was 45-54 years for men and 55-64 years for women. Living in rural areas was associated with a higher seroprevalence. In conclusion, the prevalence of anti-INKV antibodies was high in northern Sweden and was associated with male sex, older age, and rural living. The age distribution indicates exposure to INKV at a relatively early age. These findings will be important for future epidemiological and clinical investigations of this relatively unknown mosquito-borne virus.Peer reviewe

Seewis hantavirus in common shrew (Sorex araneus) in Sweden

Background Rodent borne hantaviruses are emerging viruses infecting humans through inhalation. They cause hemorrhagic fever with renal syndrome and hemorrhagic cardiopulmonary syndrome. Recently, hantaviruses have been detected in other small mammals such as Soricomorpha (shrews, moles) and Chiroptera (bats), suggested as reservoirs for potential pandemic viruses and to play a role in the evolution of hantaviruses. It is important to study the global virome in different reservoirs, therefore our aim was to investigate whether shrews in Sweden carried any hantaviruses. Moreover, to accurately determine the host species, we developed a molecular method for identification of shrews. Method Shrews (n = 198), caught during 1998 in Sweden, were screened with a pan-hantavirus PCR using primers from a conserved region of the large genome segment. In addition to morphological typing of shrews, we developed a molecular based typing method using sequencing of the mitochondrial cytochrome C oxidase I (COI) and cytochrome B (CytB) genes. PCR amplified hantavirus and shrew fragments were sequenced and phylogenetically analysed. Results Hantavirus RNA was detected in three shrews. Sequencing identified the virus as Seewis hantavirus (SWSV), most closely related to previous isolates from Finland and Russia. All three SWSV sequences were retrieved from common shrews (Sorex araneus) sampled in Vasterbotten County, Sweden. The genetic assay for shrew identification was able to identify native Swedish shrew species, and the genetic typing of the Swedish common shrews revealed that they were most similar to common shrews from Russia. Conclusion We detected SWSV RNA in Swedish common shrew samples and developed a genetic assay for shrew identification based on the COI and CytB genes. This was the first report of presence of hantavirus in Swedish shrews

Mosquito-borne viruses causing human disease in Fennoscandia—Past, current, and future perspectives

Five different mosquito-borne viruses (moboviruses) significant to human disease are known to be endemic to Fennoscandia (Sindbis virus, Inkoo virus, Tahyna virus, Chatanga virus, and Batai virus). However, the incidence of mosquito-borne virus infections in Fennoscandia is unknown, largely due to underdiagnosing and lack of surveillance efforts. The Fennoscandian moboviruses are difficult to prevent due to their method of transmission, and often difficult to diagnose due to a lack of clear case definition criteria. Thus, many cases are likely to be mis-diagnosed, or even not diagnosed at all. Significant long-term effects, often in the form of malaise, rashes, and arthralgia have been found for some of these infections. Research into mobovirus disease is ongoing, though mainly focused on a few pathogens, with many others neglected. With moboviruses found as far north as the 69th parallel, studying mosquito-borne disease occurring in the tropics is only a small part of the whole picture. This review is written with the objective of summarizing current medically relevant knowledge of moboviruses occurring in Fennoscandia, while highlighting what is yet unknown and possibly overlooked

Alphacoronavirus in a Daubenton's Myotis Bat (Myotis daubentonii) in Sweden

The ongoing COVID-19 pandemic has stimulated a search for reservoirs and species potentially involved in back and forth transmission. Studies have postulated bats as one of the key reservoirs of coronaviruses (CoVs), and different CoVs have been detected in bats. So far, CoVs have not been found in bats in Sweden and we therefore tested whether they carry CoVs. In summer 2020, we sampled a total of 77 adult bats comprising 74 Myotis daubentonii, 2 Pipistrellus pygmaeus, and 1 M. mystacinus bats in southern Sweden. Blood, saliva and feces were sampled, processed and subjected to a virus next-generation sequencing target enrichment protocol. An Alphacoronavirus was detected and sequenced from feces of a M. daubentonii adult female bat. Phylogenetic analysis of the almost complete virus genome revealed a close relationship with Finnish and Danish strains. This was the first finding of a CoV in bats in Sweden, and bats may play a role in the transmission cycle of CoVs in Sweden. Focused and targeted surveillance of CoVs in bats is warranted, with consideration of potential conflicts between public health and nature conservation required as many bat species in Europe are threatened and protected

Phylogenetic analysis of Bunyamwera and Ngari viruses (family Bunyaviridae, genus Orthobunyavirus) isolated in Kenya

Orthobunyaviruses, tri-segmented, negative-sense RNA viruses, have long been associated with mild to severe human disease in Africa, but not haemorrhagic fever. However, during a Rift Valley fever outbreak in East Africa in 1997–1998, Ngari virus was isolated from two patients and antibody detected in several others with haemorrhagic fever. The isolates were used to identify Ngari virus as a natural Orthobunyavirus reassortant. Despite their potential to reassort and cause severe human disease, characterization of orthobunyaviruses is hampered by paucity of genetic sequences. Our objective was to obtain complete gene sequences of two Bunyamwera virus and three Ngari virus isolates from recent surveys in Kenya and to determine their phylogenetic positioning within the Bunyamwera serogroup. Newly sequenced Kenyan Bunyamwera virus isolates clustered closest to a Bunyamwera virus isolate from the same locality and a Central African Republic isolate indicating that similar strains may be circulating regionally. Recent Kenyan Ngari isolates were closest to the Ngari isolates associated with the 1997–1998 haemorrhagic fever outbreak. We observed a temporal/geographical relationship among Ngari isolates in all three gene segments suggesting a geographical/temporal association with genetic diversity. These sequences in addition to earlier sequences can be used for future analyses of this neglected but potentially deadly group of viruses.Scholarship to Collins Odhiambo by the Swedish International Development Cooperation Agency (SIDA) through the African Regional Postgraduate Programme in Insect Science (ARPPIS).http://journals.cambridge.org/action/displayJournal?jid=HYGhb2016Medical Virolog