Growth Performance and Innate Immune Response of Clarias gariepinus Infected with Aeromonas hydrophila fed diets fortified with Curcuma longa leaf

The use of antibiotics as diseases control agents in aquaculture has become cantankerous due to rise in drugresistant bacteria such as Aeromonas hydrophila which has been reported to cause huge biological and economic losses. Studies have revealed antibacterial potential of some botanicals such as Curcuma longa as alternative. However, there is rarity of information on the use of Curcuma longa as growth promoter and disease control agents in Clarias gariepinus. Hence, effects of Curcuma longa on growth performance and innate immune response of Clarias gariepinus infected with Aeromonas hydrophila were evaluated. Fish (10.30 ± 0.15 g) were fed seven isonitrogenous (40% crude protein) diets (0.0, 0.5, 1.0, 1.5, 2.0, 2.5 and 3.0%) twice daily to satiation for 12 weeks. Growth performance and innate immune responses were measured and evaluated using standard procedures. Fish at 12 weeks were challenged intra-peritoneally with Aeromonas hydrophila (5 x 105 mL) and observed for 14 days. Survival rate and relative protection were monitored. The results revealed that Clarias gariepinus fed supplemented diets had better growth and immunity against Aeromonas hydrophila at 2.5% inclusion level and therefore could be used as immunodulation against Aeromonas infection

INDUCTION OF NORMOCYTIC-NORMOCHROMIC ANAEMIA IN Clarias gariepinus (Burchell, 1822) EXPOSED TO ACUTE CONCENTRATION OF 1, 1-dimethyl 4,4-bipiridillium (PARAQUAT) UNDER LABORATORY CONDITIONS

fish were exposed to test water separately diluted with acute concentrations of paraquat of 0, 15, 20, 25 and 30mg/L. A 96Hrs exposure to acute concentrations of the toxicant resulted in normocytic-normochromic anaemia in the exposed fish. Blood indices attributable to normocytic-normochromic anaemia was observed with a significant (p<0.05) decrease in haemoglobin, haematocrit, red blood cells compared with fish in the control test: Mean corpuscular volume (MCV), mean corpuscular haemoglobin (MCH) and mean corpuscularhaemoglobin concentration (MCHC) were not significantly different (p>0.05). White blood cells, lymphocytes, monocytes, Neutrophils, eosinophil and basophil were also not significantly different (p>0.05) with increasing concentrations of the toxicant&nbsp

Occurrence of Klebsiella Species in Cultured African Catfish in Oyo State, South-West Nigeria

Over the years, the increase in population, incomes, and demograph has lead to the increase in the consumption of fish as a result of its nutritional values. Clarias gariepinus is the most cultured fish species in Nigeria and attracts significant economic value making it a species of interest. Fish is capable of habouring diseases and therefore, must be safe and free of infectious pathogens if aquaculture should fulfill its potential. Infectious disease has being one of the major causes of death worldwide in recent times. Klebsiella species in the family of enterobacteriacea causes urinary tract infections, pneumonia, septicemias and soft tissue infections in human. They are opportunistic pathogens found the gastrointestinal tract of the host and spread rapidly thereby capable of causing nosocomial outbreaks. The study examined the prevalence of Klebisiella species in fish tissues in Oyo State, Nigeria. A total of seven hundred and fifty-six (756) fish organs from one hundred and eight (108) fish were examined for Klebsiella investigation. Fish of body weight ranges between 300g to 1300g were used for this study using stratified methods. The samples were examined using standard methods, biochemical characterization methods were employed in this study and data obtained were analysed using descriptive statistics. The results show that all the 66 isolates were gram-negative, did not haemolysis sheep blood, catalase positive, oxidase negative, non-motile, and ferment lactose, sucrose and mannitol sugars. Percentages of klebsiella species occurrence were 22.22% in forest zone and 40.72% in savannah zone. Fish with total length 51-60cm had highest incidence (52.17%), and body weight of 601-900g had highest incidence (57.14%). Generally, skin, gill, liver and muscle were the major location of Klebsiella species occurrence ranges from 11% to 14.81%. Therefore occurrence of Klebsiella species in higher in savannah zone than forest zone. The distribution of the klebsiella in fish in Oyo State shows that it is a problem present in fish tissues.Key words: Klebsiella, Occurrence, Diseases, infection

Mathematical analysis of a Wolbachia invasive model with imperfect maternal transmission and loss of Wolbachia infection

Arboviral infections, especially dengue, continue to cause significant health burden in their endemic regions. One of the strategies to tackle these infections is to replace the main vector agent, Ae. aegypti, with the ones incapable of transmitting the virus. Wolbachia, an intracellular bacterium, has shown promise in achieving this goal. However, key factors such as imperfect maternal transmission, loss of Wolbachia infection, reduced reproductive capacity and shortened life-span affect the dynamics of Wolbachia in different forms in the Ae. aegypti population. In this study, we developed a Wolbachia transmission dynamic model adjusting for imperfect maternal transmission and loss of Wolbachia infection. The invasive reproductive number that determines the likelihood of replacement of the Wolbachia-uninfected (WU) population is derived and with it, we established the local and global stability of the equilibrium points. This analysis clearly shows that cytoplasmic incompatibility (CI) does not guarantee establishment of the Wolbachia-infected (WI) mosquitoes as imperfect maternal transmission and loss of Wolbachia infection could outweigh the gains from CI. Optimal release programs depending on the level of imperfect maternal transmission and loss of Wolbachia infection are shown. Hence, it is left to decision makers to either aim for replacement or co-existence of both populations

Modelling the ecological dynamics of mosquito populations with multiple co-circulating Wolbachia strains

Wolbachia intracellular bacteria successfully reduce the transmissibility of arthropod-borne viruses (arboviruses) when introduced into virus-carrying vectors such as mosquitoes. Despite the progress made by introducing Wolbachia bacteria into the Aedes aegypti wild-type population to control arboviral infections, reports suggest that heat-induced loss-of-Wolbachia-infection as a result of climate change may reverse these gains. Novel, supplemental Wolbachia strains that are more resilient to increased temperatures may circumvent these concerns, and could potentially act synergistically with existing variants. In this article, we model the ecological dynamics among three distinct mosquito (sub)populations: a wild-type population free of any Wolbachia infection; an invading population infected with a particular Wolbachia strain; and a second invading population infected with a distinct Wolbachia strain from that of the first invader. We explore how the range of possible characteristics of each Wolbachia strain impacts mosquito prevalence. Further, we analyse the differential system governing the mosquito populations and the Wolbachia infection dynamics by computing the full set of basic and invasive reproduction numbers and use these to establish stability of identified equilibria. Our results show that releasing mosquitoes with two different strains of Wolbachia did not increase their prevalence, compared with a single-strain Wolbachia-infected mosquito introduction and only delayed Wolbachia dominance

A Systematic Review of Mathematical Models of Dengue Transmission and Vector Control: 2010–2020

Vector control methods are considered effective in averting dengue transmission. However, several factors may modify their impact. Of these controls, chemical methods, in the long run, may increase mosquitoes’ resistance to chemicides, thereby decreasing control efficacy. The biological methods, which may be self-sustaining and very effective, could be hampered by seasonality or heatwaves (resulting in, e.g., loss of Wolbachia infection). The environmental methods that could be more effective than the chemical methods are under-investigated. In this study, a systematic review is conducted to explore the present understanding of the effectiveness of vector control approaches via dengue transmission models

Screening of selected medicinal plants for their antifungal properties

Background: The rising incidence of fungal infections has created the need for the next generation of antifungal agents, as many of the currently available ones either have adverse effects, or are not active against emerging or re-emerging fungi, leading to the fast progression of resistant strains. Objectives: This study aims at evaluating the antifungal activities of some medicinal plants used traditionally for treating skin infections in Nigeria. Methods: In vitro antifungal activities of seven indigenous plants (Leptadenia hastate, Lawsonia inermis, Hyptis suaveolens, Luffa cylindrica, Jatropha curcas, Pterocarpus erinaceous and Afromaxia laxiflora) were screened against Candida albicans ATCC 10231, Candida tropicalis ATCC 13803, clinical strains of Candida albicans, Candida tropicalis, Trichophyton rubrum, Microsporum canis and Epidermophyton floccosum using agar dilution and micro broth dilution methods. Terbinafine and fluconazole were used as reference standards for comparism. Results: The results showed that the ethanol and ethyl acetate extracts of the plants produced better antifungal effects than the hexane and water extracts. Luffa cylindrica and H. suaveolens exhibited the strongest inhibitory activity against all the fungi tested with minimum inhibitory concentration values ranging between 250 and 1000 ag/mL. Conclusion: The plants screened could serve as leads for the development of new antifungal drugs.Key words: Antifungal, agar dilution, micro broth dilution, minimum inhibitory concentration

Mathematical analysis of a two-strain tuberculosis model in Bangladesh

Tuberculosis (TB) is an airborne infectious disease that causes millions of deaths worldwide each year (1.2 million people died in 2019). Alarmingly, several strains of the causative agent, Mycobacterium tuberculosis (MTB)—including drug-susceptible (DS) and drug-resistant (DR) variants—already circulate throughout most developing and developed countries, particularly in Bangladesh, with totally drug-resistant strains starting to emerge. In this study we develop a two-strain DS and DR TB transmission model and perform an analysis of the system properties and solutions. Both analytical and numerical results show that the prevalence of drug-resistant infection increases with an increasing drug use through amplification. Both analytic results and numerical simulations suggest that if the basic reproduction numbers of both DS (R0s) and DR (R0r) TB are less than one, i.e. max[R0s, R0r]max[R0s,1], then DS TB dies out but DR TB persists in the population, and if R0s>max[R0r,1] both DS TB and DR TB persist in the population. Further, sensitivity analysis of the model parameters found that the transmission rate of both strains had the greatest influence on DS and DR TB prevalence. We also investigated the effect of treatment rates and amplification on both DS and DR TB prevalence; results indicate that inadequate or inappropriate treatment makes co-existence more likely and increases the relative abundance of DR TB infections

Can environmental DNA be used to detect first arrivals of the cane toad, Rhinella marina, into novel locations?

Eradicating invasive species is difficult, but success is more likely when populations are small after arrival. The cane toad, Rhinella marina, is an invasive pest species that threatens native fauna worldwide. Increasingly, environmental DNA (eDNA) is used as a technique to monitor the presence of invasive species given its power to detect low numbers of individuals. We aimed to investigate eDNA persistence in freshwater at three different temperatures (25, 30 and 35°C) and eDNA detection thresholds for R. marina using controlled experiments in aquaria. For the latter, two water volumes and two cane toad exposure times were used (800 or 200 L volume with 5 or 30 min exposure). A 15‐ml water sample was collected from each replicated aquaria and preserved with 5 ml Longmire's buffer. Environmental DNA was extracted and four technical quantitative PCR replicates were analyzed targeting the cane toad 16S rDNA mitochondrial gene. Environmental DNA decayed rapidly in water and was reliably detected for up to 3 days after cane toad removal, regardless of the temperature treatment. Also, cane toad eDNA was detected in the water after a 5‐min initial exposure of a single individual in 800 L of water. Under the physical parameters tested here, a positive detection means that a cane toad has been in contact with the water body between 1 and 3 days prior to the sampling event. The results of the present study show the importance of eDNA for determining the presence of a species that occurs at low abundance in a small water body, such as at the onset of a cane toad invasion