Open Access Case Study

In-vitro Susceptibility of Candida Pathogens Isolated From Clinical Specimens to Available Antifungal Agents in Nigeria

D. Olusoga Ogbolu, O. A. Terry Alli, O. S. Adewumi, A. S. Oluremi

International Journal of TROPICAL DISEASE & Health, Page 80-86
DOI: 10.9734/IJTDH/2015/16116

Aim: To characterize clinical isolates of Candida species from a tertiary hospital in South West Nigeria and also to determine their susceptibility to antifungal agents in order to guide in the course of empirical treatment of patients visiting hospitals in Nigeria.
Study Design: This was a cross sectional study.
Place and Duration of Study: Medical Microbiology and Parasitology Laboratory, LAUTECH Teaching Hospital, Osogbo, Nigeria. Study duration was Five (5) months.
Methods: One hundred and twenty-four Candida species obtained from various body sites were identified and speciated using conventional and analytical profile index (API) for Candida and the susceptibility to 5 antifungal agents was determined using disc and macrodilution methods.
Results: Highest number of Candida was obtained from urine, 44 (35.5%); followed by High Vaginal Swabs (HVS), 32 (25.8%) and blood, 20 (16.1%). Highest frequencies were obtained from C. Krusei and C. tropicalis, 32 (25.8%) each, followed by C. Albicans and C. pseudotropicalis, 24 (19.4%) each, and C. gulliermondii,12 (9.7%). Susceptibility to amphotericin B was the highest (74%),followed by itraconazole (52%) while least susceptibility was found in ketoconazole (19.0%).Strains of C. krusei and C. guilliermondii demonstrated 100% resistance to fluconazole and clotrimazole, respectively. MIC50 in most cases were greater than clinical break points and MIC90 values ranged between 16 and >64 µg/ml for all antifungal agents except amphotericin B, 0.5 to 1 μg/ml.
Conclusion: Majority of Candida isolates are resistant to azole drugs. Amphotericin B is a reasonable alternative drug for empirical treatment of candidiasis since routine drug susceptibility testing Candida does not exist yet in any hospital in Nigeria.

Open Access Original Research Article

Trend in Malaria Incidence Rates (2006-2013) in Edo State, Nigeria

A. Ebomwonyi, A. O. Omoregie, M. A. E. Noutcha, S. N. Okiwelu

International Journal of TROPICAL DISEASE & Health, Page 40-48
DOI: 10.9734/IJTDH/2015/15093

Background: Detailed information on the severity of malaria and other diseases across operational areas is a prerequisite to the judicious utilization of limited effective tools for the control in Africa.
Methods: Records of Patients, from the 18 Local Government Areas (LGAs), who visited Health Centres across Edo State, 2006-2013, and stored in the Ministry of Health database in Benin City were analysed. Patients were placed in 3 groups (out-patients, In-patients, Pregnant Women).
Human population data, in the 18 LGAs over the period were obtained from the National Population Commission. Malaria incidence rates were estimated. The proportions of patients in the 3 categories annually across LGAs were determined.
Results: Malaria Incidence rates increased 2-13 folds over the period in all LGAs, except in Esan West where there was a significant reduction in 2011. The highest rates were recorded at Esan Central (13.66%) and Uhunmwonde (11.50%). The highest increases in the proportions of patients with severe malaria were at Uhunmwonde, Igueben and Orhionmwon LGAs. In contrast, reductions in the proportions of severe malaria were in Esan Northeast and Owan West. The highest increases in the proportions of pregnant women patients were in Esan central and Esan West; in contrast, major reductions were observed at Oredo and Igueben.
Conclusion: The multi-faceted Federal and State Governments Intervention Policies and Strategies have apparently not been effective in the State. There is an urgent need for the intensification of efforts, including increase in the number of ITNs and upgrading of facilities at the Primary Health Care Centres for holistic diagnosis.

Open Access Original Research Article

An Assessment of Immune Response to Canine Distemper Vaccination in Dogs Experimentally Infected with Ancylostoma and Trypanosome Parasites

R. I. O. Nwoha, B. M. Anene

International Journal of TROPICAL DISEASE & Health, Page 62-68
DOI: 10.9734/IJTDH/2015/14905

The immunological alteration in vaccinated dogs with single hookworm, Ancylostoma caninum (A. c) and conjunct infection with Trypanosoma congolense (T. c) and Trypanosoma brucei (T. b) was determined. Sixteen dogs grouped into 4 of 4 members each were used. Group 1 was the uninfected control, GPII was infected with A. c, GPIII was infected with A. c /T. c, and GPIV was infected with T. b/A. c. The dogs were first inoculated with canine distemper (CD) vaccine before infection with A. c 4 weeks post vaccination. Two weeks later, both GPIII and GPIV were superposed with trypanosome infection. Prepatent period of A. c was 14 to 16 days in single A. c group and 13 to 14 days in conjunct trypanosome/A. c. The prepatent period of conjunct T. c/A. c was 9.00±1.10 days and 3.00±1.40 days, in conjunct T.bb/A. c. The protective antibody against CDV was considered using haemagglutination inhibition test (HIT) titer >100 as a cut off for sero-conversion. At one week post vaccinations, the antibody titer against canine distemper (CDV) and anti-rabies in all the vaccinated groups (GPI, GPII, GPIII, and GPIV) significantly increased (p<0.05) and peaked at 3 weeks post vaccination. Subsequently, there was gradual significant decrease (p<0.05) in all the infected groups (GPII, GPIII and GPIV). The decrease in the conjunct groups (GPIII and GPIV) was higher compared to the single infections (GPII). Treatment with diminazene aceturate and mebendazole in all the groups did not significantly (p<0.05) improve antibody response in the dogs. A secondary vaccination administered at 12 weeks post- primary vaccination significantly increased (p<0.05) the antibody titer with a peak 3 weeks post- secondary vaccination. In conclusion, both trypanosomes and A. c induced primary immune suppression in antibody response to vaccination which improved on secondary vaccination in the infected dogs.

Open Access Original Research Article

Analysing Host Preference Behavior of Phlebotomus argentipes (Diptera: Psychodidae) Under the Impact of Indoor Residual Spray

Vijay Kumar, Lokesh Shankar, Aarti Rama, Shreekant Kesari, Diwakar Singh Dinesh, Gouri Shankar Bhunia, Pradeep Das

International Journal of TROPICAL DISEASE & Health, Page 69-79
DOI: 10.9734/IJTDH/2015/16170

Background: Present scenario of Bihar and neighboring Indian states reveals dichlorodiphenyltrichloroethane (DDT) being an insecticide of choice for controlling the vector of Indian Visceral Leishmaniasis (VL) i.e., Phlebotomus argentipes, that had reported to attain resistance/tolerance against it, leading to the behavioral transition including host preference and selection by them. The relationship between insecticidal resistance and host preference/ selection is not yet well understood.
Objective: Exploring the host preference/selection behavior under the influence of insecticidal pressure in different biotopes of VL endemic regions in India
Methods: For this, the engorged sand flies that were collected before and after Indoor Residual Spray (IRS) were subjected for feeding behavior analysis. The parameter studied were Host Feeding Index (HFI) and Forage Ratio (FR) by analyzing Blood Meal Identification (BMI).
Results: The higher percentage of sand flies were recorded to be fed on cattle host (56.05%) with respect to the human host (30.35%) before IRS while a significant increase in cattle blood index (79.17%) in contrast to significant drop in human blood index (9.43%) was recorded during post IRS session at the study site. It establishes, cattle being potentially served as a preferred host for sand flies in contrast to other available hosts. The lowered value of FR during pre- and post-IRS respectively for human (0.77 and 0.24) as compared to the cattle (1.89 and 2.67) indicates cattle host being selectively preferred by the P. argentipes also corroborate with the results of BMI.
Conclusion: Through the study we can conclude that instead of being killed by IRS, P. argentipes has attained resistance against DDT. Under the insecticidal pressure the host preference as well as selection tendency of P. argentipes for cattle host gets enhanced under the influence of IRS, as abrupt increment was observed in the FR’s post-IRS. While, the avoidance tendency of insects from the human hosts in favor of other available hosts’ viz., cattle, goat, pigs, etc. with slight decrement in the forage ratios for the human hosts during the IRS was also observed. Thus, under the impact of IRS, P. argentipes has changed its behavior from endophilic to exophilic and migrated from the human hosts at the periphery area of sprayed houses towards much safer zone, i.e., deserted houses, nearby gardens, bushes, etc for their survival for feeding cattle i.e., preferred host, lying in unsprayed horizon. Therefore, change in control strategy involving the proper management of insecticide resistance is very much needed to tackle the vector outbreak and hence menace caused by them.

Open Access Review Article

Haematophagy and Opportunities for Symbiotic Control of Insect Vectors of Human Protozoan Diseases

Mulambalah Chrispinus Siteti, Siteti Darwin Injete

International Journal of TROPICAL DISEASE & Health, Page 49-61
DOI: 10.9734/IJTDH/2015/16149

Insect vector-symbiotic relationships are widely reported in literature with several microorganisms reported to play a key role in growth, development, survival and evolutionary success of insect disease vectors. Symbiotic bacteria are prevalent in insects like mosquitoes, sand flies, tsetse flies that are known efficient vectors of tropical diseases. Several studies have been undertaken to determine the mechanisms of the insect host-symbiotic relationships with the aim of developing new strategies to control human vector borne diseases. Some bacterial symbionts have evolved together with the respective insect hosts such that the hosts cannot survive without them. This is the basis of an intervention strategy known as symbiotic control. It is a recent multi-pronged approach that targets symbiotic microorganisms to control insect disease vectors and possibly interfere with their vectorial capacity. The strategy is promising and has recently generated a lot of research interest. Three such approaches have been reported and are: the interference and destabilization of microbial symbionts essential for insect vector survival; changing the genetic make-up of symbionts so that they generate and express anti-parasite agents within the insect host; and the introduction of other microorganisms that may eventually negatively affect the longevity and vector competence of the offspring in future populations. The availability of new molecular techniques has made the understanding of symbiotic relationships more clear. With sustained and increasing research interest and recent findings in insect-symbiotic associations, there is high possibility that soon we will have many insect-vector control programs utilizing this information and techniques. In this review we highlight the evolution of blood feeding behavior in insect disease vectors, new findings and developments on microbial symbiosis in mosquitoes, sand flies, triatomine bugs and tsetse flies that are feasible and therefore form basis for formulating symbiotic control strategies for major human insect borne parasitic protozoan diseases: malaria, leishmaniasis and trypanosomiasis.