First evaluation of antibody responses to Culex quinquefasciatus salivary antigens as a serological biomarker of human exposure to Culex bites: A pilot study in Côte d’Ivoire

Background Culex mosquitoes are vectors for a variety of pathogens of public health concern. New indicators of exposure to Culex bites are needed to evaluate the risk of transmission of associated pathogens and to assess the efficacy of vector control strategies. An alternative to entomological indices is the serological measure of antibodies specific to mosquito salivary antigens. This study investigated whether the human IgG response to both the salivary gland extract and the 30 kDa salivary protein of Culex quinquefasciatus may represent a proxy of human exposure to Culex bites. Methodology/Principal findings A multidisciplinary survey was conducted with children aged 1 to 14 years living in neighborhoods with varying exposure to Culex quinquefasciatus in the city of Bouaké, Côte d’Ivoire. Children living in sites with high exposure to Cx quinquefasciatus had a significantly higher IgG response to both salivary antigens compared with children living in the control site where only very few Culex were recorded. Moreover, children from any Culex-high exposed sites had significantly higher IgG responses only to the salivary gland extract compared with children from the control village, whereas no difference was noted in the anti-30 kDa IgG response. No significant differences were noted in the specific IgG responses between age and gender. Sites and the use of a bed net were associated with the level of IgG response to the salivary gland extract and to the 30 kDa antigen, respectively. Conclusions/Significance These findings suggest that the IgG response to Culex salivary gland extracts is suitable as proxy of exposure; however, the specificity to the Culex genus needs further investigation. The lower antigenicity of the 30 kDa recombinant protein represents a limitation to its use. The high specificity of this protein to the Culex genus makes it an attractive candidate and other specific antibody responses might be more relevant as a biomarker of exposure. These epidemiological observations may form a starting point for additional work on developing serological biomarkers of Culex exposure.

In vitro analysis of human immune response (IgG) against salivary gland extract of dengue vector from dengue hemorrhagic fever (DHF) endemic area in Jember, Indonesia

The mosquito species Ae. aegyptiand Ae. albopictusare two potential vectors of dengue fever. The salivary glands of these species contain substances that play a role in the transmission of pathogens. These include vasodilators and immunomodulatory compounds. Immunomodulatory components can modulate the host immune system by producing specific antibodies (IgG). This study aims to investigate the human immune response (IgG) against the salivary gland extract of Ae. aegyptiand Ae. albopictus. Samples were collected from individuals who were Dengue patients, as well as healthy individuals and neonates from the Jember endemic area. Results show that the levels of IgG response vary across the individual. Generally, Dengue patients and healthy people in the DHF-endemic area had higher levels of IgG. The highest immune response was found in DHF patients, followed by healthy persons, and finally the neonate samples, respectively.

Salivary gland extract from the deer tick, Ixodes scapularis, facilitates neuroinvasion by Powassan virus in BALB/c mice

Powassan virus (POWV) is a neuroinvasive flavivirus transmitted to mammals by the bite of ixodid ticks. In this study, we sought to investigate the impact of tick salivary gland extract (SGE) on POWV neuroinvasion. BALB/c mice were footpad inoculated with either a high dose or a low dose of POWV, with and without Ixodes scapularis salivary gland extract. Brain and spinal cord were extracted daily, and immunohistochemical techniques were used for temporal tracking of POWV antigen. The temporal pattern of POWV staining showed a caudal to rostral spread of POWV in the brains of mice from both high dose infection groups. For the high dose infection groups, the presence of tick SGE did not influence the spread of POWV in the brain. Mice infected with the low dose of virus alone did not present POWV staining in the brain; however, in the presence of SGE, low dose infected mice presented scattered foci of POWV-infected cells throughout the brain. This study shows that tick SGE facilitates POWV neuroinvasion when mice are infected with the lower dose of POWV. We also found two patterns of central nervous system invasion that were directly influenced by the dose of POWV administered.

Standardization of Critical Quality Indicators of Liposomes of Siberian Musk Deer Prepucial Gland Extract

The liposomal form of a new original remedy based on the preputial gland of Siberian musk has been standardized and characterized. For the preparative isolation of musk musk liposomes, an effective and scalable method of high-pressure homogenization was used. The resulting liposomal product was characterized by transmission electron microscopy, dynamic light scattering, preparative and analytical chromatography, and chromatography-mass spectrometry. A specification for the liposomal form of the extract of the prepucial gland of Siberian musk deer, including all critical indicators of the product quality, has been developed. Homogeneous dispersions of musk musk liposomes with uniform size distribution — with distribution maxima at 50 and 240 nm — were obtained. The high physical and chemical stability of the liposomal dispersion was established: the zeta potential of the obtained nanoparticles was -5...-35 mV. The degree of inclusion in the liposomes of the target components of musk musk according to gel-size chromatography and mass spectrometry for musk liposomes for steroid components and total protein was 58–75%. The developed quality indicators of the liposomal product allow for serial standardization of the manufacturing quality control and form the prerequisites for guaranteed high efficiency of the product based on the liposomal form of musk musk extract as an adaptogen of natural origin with an enhanced and pronounced effect.

Infecting mosquitoes alters DENV-2 characteristics and enhances hemorrhage-induction potential in Stat1-/- mice

Dengue is one of the most prevalent arthropod-borne viral diseases in humans. There is still no effective vaccine or treatment to date. Previous studies showed that mosquito-derived factors present in saliva or salivary gland extract (SGE) contribute to the pathogenesis of dengue. In this study, we aimed to investigate the interplay between mosquito vector and DENV and to address the question of whether the mosquito vector alters the virus that leads to consequential disease manifestations in the mammalian host. DENV2 cultured in C6/36 cell line (culture-DENV2) was injected to Aedes aegypti intrathoracically. Saliva was collected from infected mosquitoes 7 days later. Exploiting the sensitivity of Stat1-/- mice to low dose of DENV2 delivered intradermally, we showed that DENV2 collected in infected mosquito saliva (msq-DENV2) induced more severe hemorrhage in mice than their culture counterpart. Msq-DENV2 was characterized by smaller particle size, larger plaque size and more rapid growth in mosquito as well as mammalian cell lines compared to culture-DENV2. In addition, msq-DENV2 was more efficient than culture-DENV2 in inducing Tnf mRNA production by mouse macrophage. Together, our results point to the possibility that the mosquito vector provides an environment that alters DENV2 by changing its growth characteristics as well as its potential to cause disease.

Identification and characterisation of female released sex pheromone components of jute semilooper, Anomis sabulifera Guenee (Lepidoptera: Noctuidae)

Aim: Identification and characterization of female released sex pheromone components of jute semilooper, Anomis sabulifera Guenee (Lepidoptera: Noctuidae) from female pheromone gland extracts. Methodology: Electroantennogram (EAG) was carried for studying the antennal response; Gas Chromatography coupled with Electro antenna Detector (GC-EAD) was conducted for studying the antennal response of eluted compounds from female pheromone gland extract; Gas Chromatography and Mas Spectrophotometry (GC-MS) was conducted for characterization or getting complete profile of compounds present in the female pheromone gland extract based on retention times. Wind tunnel assay was conducted for studying the behavioural responses of eluted compounds from the female pheromone gland extract. Results: GC-MS profile of female pheromone gland extract revealed that the GC-EAD active region constituted (6Z,9Z)-heneicosadiene, (3Z,6Z,9Z)-heneicosatriene as active compounds. Preliminary wind tunnel studies for olfactory and behavioural responses showed blend of (6Z,9Z)-heneicosadiene (3 parts) + (3Z,6Z,9Z)-heneicosatriene (1 part) enticed 60% male adults. Interpretation: (6Z,9Z)-heneicosadiene and (3Z,6Z,9Z)-heneicosatriene are likely to be active pheromone components present in female sex pheromone glands. Blending of these two compounds in precise ratio can enhance the effectiveness of pheromone and can be used as effective strategy in jute IPM. Key words: Anomis sabulifera, Jute semilooper, Noctuidae, Sex pheromone, (6Z,9Z)-heneicosadiene, (3Z,6Z,9Z)-heneicosatriene

Comparative study on African catfish (Burchell, 1822) hypophysation using ovaprim and chicken pituitary gland extract

Comparative study on African catfish hypophysation indices using ovaprim and chicken pituitary gland extract (CPGE) was carried out. Sixteen (16) African catfish brood stocks between 1100 and 2300 g in ratio 2:1 and four (4) numbers of layer birds (Gallus gallus domesticus) between 1200 and 2200 g in ratio 1:3 were used respectively. The experiment was batched into “A” and “B”. Batch ‘A’ was placed on ovaprim while batch ‘B’ was placed on CPGE. An indoor hatchery vat, measuring 0.6096 m x 1.8288 m x 0.3048 m each was used for the incubation. Digital measuring kits were used to monitor water quality parameters and measurement of the brood stocks weights independently. Brood stocks on ovaprim and CPGE treatments had the following mean hypophysation indices in these order: fecundity (11100±7690 and 17760±13863), latency period (9.53±0.54 and 9.77±0.49), fertilization percentage (94.03±5.90% and 90.6±10.11%), hatchability percentage (75.6±0.81% and79.35±10.27%), number of eggs produced (5889±657.37 and 9403.33±589.80), total number of larvae hatched (4717.33±1111.0 and 7111.33±506.64), SGR (0.67±0.31 and 1.1±0.31), and survival rate (64.81±0.71 and66.24±2.19) respectively. There was no significant difference (p = 0.05) in the mean values of fecundity, latency period, fertilization and hatchability percentages in both treatments but there was significant difference (p ≤ 0.05) in number of eggs produced and total number of larvae hatched in both treatments. The water quality parameters were within the range for induced breeding techniques and there was no significant difference (p= 0.05) in both experiments. Both ovaprim and CPGE had excellent results from the induced breeding of Clarias gariepinus and yielded good results. Therefore, CPGE could be recommended from the view point of excellent results and its availability from chicken slaughter houses as against ovaprim which are imported.