Zooplankton Diversity in Tropical Freshwater

 

The tropical freshwater are known to exhibit less biodiversity as compared to more temperate waters.The lack of such greater biodiversity in fresh water ecosystem is due to several factors

These factors are known to impede or limit the amount of biodiversity in fresh water. The implicating factors are; all year round predation by the fish species in such water bodies that graze continually on the planktonic communities in such tropical freshwaters, temperature and salinity are also important factors that limit zooplankton species diversity.

In comparison to marine habitat, freshwater habitat are also much less biological diverse. Marine  habitat harbours much more zooplankton communities than freshwaters. The observable differences are very much likely to be due to great antiquity of  the marine environment, depth of the water body and evolutionary continuity found in the marine environments.

Even much older lakes like lake Tangayika, are not biologically diverse when compared to oceans. In the tropical freshwaters, planktonic animals are dominated by four major groups which are:

·        Protists, including protozoans and heterotrophic flagellates.

·        Rotifers and other classes of crustaceans.

·        The Cladocerans and

·        The Copepods.

It is noteworthy that protistan zooplankton are very important microbial consumers and are functional in organic carbon utilization and nutrient recycling.

On the other hand, flagellates are the most abundant component of the protozooplankton. Whereas ciliates are largely holozoic and high feeding rate on bacteria, algae, particulate detritus.

The sarcodine protozoa only occasionally reach modest occurrence.

Biomanipulation

Biomanipulation is a biological engineering in which manipulation of certain herbivorous organisms lead to the reduction of certain algal groups that are not wanted

It can also be said to be a biological process of elimination or reduction of the effect of eutrophication of a water body.

Biomanipulation is achieved when planktivorous fishes are reduced,which in turn leads to the increase in the density or number of Cladoceran zooplankton. And the grazing of these large Cladocerans on algal species in the water bodies in turn reduces their abundance. The reduction in the algal population, thus reduce the turbidity of the water caused by algal bloom.

To achieve biomanipulation, planktivorous fishes have to be reduced by several methods, among which are, the introduction of carnivorous fishes into the water body or by intensively harvesting planktivorous fishes found in the eutrophic water.

Importance of Biomanipulation

Biomanipulation is known to have several advantages where it is properly practiced.

·        It can reduce eutrophication in water bodies

·        It reduces turbidity caused by algal bloom

·        It removes species of algae that are known to produce toxic substances            (cyanotoxins)

·        It helps in reducing the eutrophication on other aquatic animals

·        It is an important alternative in the use of algicidal chemicals

Effective Biomanipulation

For biomanipulation to be effective, it has to be combined with other several methods.

Basically, reduction of nutrients getting into the affected water body has to be put in place; proper agricultural practices should also be put in place too. In addition to that, biomanipulation must be done consistently year in, year out before its benefits can be properly harnessed.

PREVALENCE OF MALARIA AMONG CHILDREN ATTENDING TWO HOSPITALS IN GOMBE,Nigeria

BY

SARKI ALHAJI

AUGUST, 2009

ABSTRACT

A study of Malaria Parasites among children aged 1-10 years attending Specialist Hospital and Federal Medical Centre Gombe, Gombe State, was conducted between March and May 2009. Blood smears were obtained from 200 children from the two hospitals, forty five of the children were tested again using rapid test kits method for Plasmodium falciparum only. Out of the 200 children examined, 128 (64%) had plasmodium infections. With Specialist Hospital Gombe 63 (96.9%) having a higher prevalence rate than Federal Medical Centre Gombe 65 (48.1%) (Table 1&2). Furthermore, the prevalence of plasmodium infections showed that there was no significant difference among the age groups, with age group 4-6 (17.5%) and 7-10 (17.5%) having the same prevalence rates respectively, age groups 1-3 (29%) having highest prevalence rate. Males (34%) had a significant higher prevalence rate than females (30%). The study revealed that Malaria is a major public health problem among the children aged 1-10 years in Gombe. Hence, preventive measures are necessary.

INTRODUCTION

Background of the Study

          Malaria is an acute and chronic disease caused by an obligate intracellular protozoan of the genus plasmodium (Eneanya, 1996).

The Malaria parasite was discovered in 1880 by Laveran a military physician working in Constantine Algeria (Ksogstad, 1996).

          Malaria is a parasitic disease of mammals including birds and reptiles. It is the most common disease amongst school children and young adults in Africa. (CDC, 2000).

          Malaria is a life threatening diseases transmitted by the female anopheles mosquito. Malaria is by far the most important insect transmitted disease (Curtis, 1991).

          The female mosquito needs blood meal for egg development, hence the need to bite. Out of approximately 430 known species of anopheles, only 30-50 transmit malaria in nature (FMOH, 1991).

The successful development of the malaria parasite in the mosquito vector (from the “gametocyte” stage to the “sporozoite” stage) depends on several factors. The most important is ambient temperature and humidity (higher temperatures accelerate the parasite growth in the mosquito) and whether the anopheles survives long enough to allow the parasite to complete its cycle in the mosquito host (“Sporogonic” or extrinsic” cycle, duration is 10 to 18 days). Differently from the human host, the mosquito host does not suffer noticeably from the presence of the parasites (CDC, 2006).

          The vectors of human malaria all belong to the genus Anopheles whose adults are recognized by their “tail in the air” posture, dapped wings in most tropical species and long pair of palps beside the proboscis in the female (Curtis, 1991).

          Malaria remains the important parasitic disease in the tropics with over half of the world’s population being at risk. In African alone, malaria has been estimated to cause the dearth of million children annually (WHO, 2003).

          WHO estimate that there are 300-500 million cases of clinical malaria per year, with 1.4-2.6 million deaths, mainly among African children (WHO, 2003).

          Malaria is therefore a major cause of infant mortality and is the only insect borne parasitic disease comparable in impact to the world’s major killer disease like diarrhea, acute respiratory infections, tuberculosis and AIDS (Curtis, 1991).

          In Nigeria, malaria is the most common cause of out patient to hospitals and it consistently rank among the three most important cause of death among children (CDC, 2000).

          Four species of malaria parasites can affect humans under natural conductions: Plasmodiurn falciparum, P. vivax, P. ovale and P. malariae. The first two species cause the most infections worldwide. Plasmodium faicIparum is the agent of severe, potentially fatal malaria, causing an estimated 700,000-2.7 million deaths annually, most of them in young children in Africa (CDC, 2006).

          Plasmodium vivax and P. ovale have dormant hirer state parasites (“hypnozoites”), which can reactive (“relapse”) and cause malaria several months or years after the infecting mosquito bite (CDC, 2006).

Plasmodium malariae produced long-lasting infections and if left untreated can persist asymptomatically in the human host for years, even a life time (CDC, 2006).

Justification of the Study

·        Information on malaria at local level is scanty and the effects of the diseases on the population are not well documented for which reason, this study has been designed to provide baseline pre-control data required for planning.

·        Plasmodium falcparum is the most virulent in the tropics and is resistant to various anti-malaria drugs.

·         

Scope and Limitation of the Study

          This study is restricted to two hospitals in Gombe i.e. Federal Medical Centre and Specialist Hospital Gombe as sample hospitals for samples collection and analysis.

Aims and Objectives

          The aim of this study is to screen children for the species of

Plasmodium causing malaria in humans.

          The objective is to determine the prevalence of malaria among children between the ages of 1-10 years.

MATERIALS AND METHOD

Study Area

The area of the study is the federal medical centre Gombe and Specialist Hospital Gombe, the capital of Gombe State Lies between latitude 11⁰ 8¹ N and 11⁰ 24¹ N, longitude 11⁰ 02¹ E and 11⁰ 18¹ E. It has a population of about 2.1 million people and an area of 18,000 km². The temperature averages 30°C with an annual rainfall of 52cm, the predominated occupation of its people is agricultural and livestock rearing.

Study Population and Sample Size

This study was done on children aged 1-10 years attending Federal Medical Centre and Specialist Hospital Gombe. Two hundred children were screened within three months i.e. Mach, April and May for the presence of malaria parasites. 135 children were screened in Federal Medical Centre where as 65 children in Specialist Hospital Gombe.

Laboratory Procedures

Sample Collection

Blood samples were collected with care and adequate safety precautions to ensure test result are reliable, contamination of the samples was avoided and infection from blood transmissible pathogens was also prevented. Protective gloves were worn when collecting and handling blood samples. The blood samples were collected into EDTA bottle/container which were labeled with information such as Name of the Patient, Date, Sex, Age, Laboratory and Hospital Numbers.

Thin/Thick Blood Film Preparation

A small drop of blood was placed on a clean microscopic slide near the end of a slide, a spreader was used to smear a blood steadily across the slide in a steady even movement at an angle of 45°, and the slide was allowed to dry and labeled appropriately.

Staining Procedure

          1 volume of Leishman stain was flooded on the slide for few minutes, 2 volumes of buffered distil water of PH 6.8 was added and left for further 10 minutes, the slide was washed thoroughly under tap water to differentiate (the colour should be salmon pink), the slide was left to dry and back of the slide was clean with cotton wool soaked in alcohol.

Microscopic Examination

          A drop of oil immersion was placed on a stained slide and viewed under compound microscope in order to identify the Plasmodium parasites as well as the intensity of the parasites. Positive or negative results were recorded accordingly.

Test Kits Procedure

          The test kits method was used in 45 samples as fast diagnostic method for Plasmodium falciparum.

          The sealed pouch was opened by tearing along the notch, test strip from the pouch was removed, 10il sample was added on the absorbant area of test strip and the diluent for three drops was added, the result was read at 10 minutes in a result area.

RESULTS

          Table 1 shows the distribution of Malaria in relation to age in Specialist Hospital Gombe. Out of 65 children that were tested, age 1-3 years 28 were tested and these number 28 (43.1%) were found infected, age 4-6 years 17 were tested and 16 (24.6%) were found infected and also age 7-10 years 20 were tested and 19 (29.2%) were found infected.

          Table 2 shows the distribution of Malaria in relation to age in Federal Medical Centre Gombe. Out of 135 children that were tested, age 1-3 years 64 were tested and 30 (22.2%) were found infected, age 4-6 years 36 were tested and 19 (14.1%) were found infected and age 7-10 years; 35 were tested and also 16 (11.9%) were found infected.

          Table 3 shows the overall distribution of Malaria in relation to age. Out of 200 children that were tested, age 1-3 years; 92 were tested and out of these number, 58 (29%) were found infected, age 4-6 years; 53 were tested and out of these number, 35 (17.5%) were found infected and age 7-l0years; 55 were tested and out of these number, 35 (17,5%) were also found infected.

Table 1: Distribution of malaria in relation to age at specialist hospital Gombe

Age (year)	Number examined	Number infected	% Infected
1-3	28	28	43.1%
4-6	17	16	24.6%
7-10	20	19	29.2%
Total	65	63	96.9%

Table 2: Distribution of malaria in relation to age at Federal Medical Centre Gombe.

Age (year)	Number examined	Number infected	% Infected
1-3	64	30	22.2%
4-6	36	19	14.1%
7-10	35	16	11.9%
Total	135	65	48.1%

Table 3: Overall distribution of malaria in relation to age

Age (year)	Number examined	Number infected	% Infected
1-3	92	58	29%
4-6	53	35	17.5%
7-10	55	35	17.5%
Total	200	128	64%

Table 4: Distribution of malaria in relation to age and sex at specialist hospital Gombe

Age (year)	Number examined		Number infected		% Infected
	Males	Females	Males	Females	Males	Females
1-3	15	13	15	13	23.1%	20%
4-6	7	10	6	10	9.2%	15.4%
7-10	11	9	10	9	15.4%	13.8%
Total	33	32	31	32	47.7%	49.2%

Table 5: Distribution of malaria in relation to age and sex federal medical centre Gombe

Age (year)	Number examined		Number infected		% Infected
	Males	Females	Males	Females	Males	Females
1-3	41	28	18	12	13.3%	40%
4-6	25	11	11	8	8.4%	5.9%
7-10	12	28	8	8	5.9%	5.9%
Total	78	57	37	28	27.4%	20.7%

able 6: Overall Distribution of Malaria in Relation to age and sex

Age (year)	Number examined		Number infected		% Infected
	Males	Females	Males	Females	Males	Females
1-3	56	36	33	25	16.5%	12.%
4-6	32	21	17	18	8.5%	9%
7-10	23	32	18	17	9%	8.5%
Total	111	89	68	60	34%	30%

Figure 6: Percentage of children infected with plasmodium species at both Hospitals.

                     Overall distribution of Plasmodium parasites by sex and age which were calculated by chi-square test, concluded that there were no significant different between infection by sex and age since X2 cal value is less than X2 tab value at P <0.05 and degree of freedom 1 and 2 respectively (appendix 5 and 6).

Interpretation of Test Kits Results

Positive Result: - In addition to a pick colored control (C) line, a distinct pick colored line was also observed in the test (T) area.

Negative Result: - Only one colored line appears on the control (C) area. No apparent strip on the test (T) area.

Invalid Result: - A total absence of colour line in both regions or only one color line on the test area. It is an indication of procedure error and/or the test reagent has deteriorated.

Discussion

          This study has shown that the overall prevalence of plasmodium parasite was 64% (128/200) among children ages 1 — 10 years attending two hospitals in Gombe metropolis. The reported prevalence of plasmodium infections was high. This agreed with the work of (WHO, 2003) which reported a prevalence of (58%) malaria parasite among children in Banjul the capital of Gambia. It was observed that the prevalence in Gombe is higher than that of Gambia. Furthermore, this finding is lower when compared to (80%) prevalence reported among children in the malaria endemic village of Erunmu in Southwest Nigeria. This shows moderate prevalence of malaria in this area compared to 94% prevalence reported by (Umar, 2006) in Gombe metropolis. This could be attributed to the weather, Umar research work done in rainy season which is known to increase the prevalence of malaria since it provides more breeding sites for the vector of malaria.

          The prevalence of infection recorded for wet season in Udi Enugu State, was 59.8% (Eneanya, 1998), while 58.3% was reported for children aged 0 — 5 years in Awka, Anambra State (Mbanugo and Ejims, 2000) and 61 % recorded in Abuja (Matur et al, 2001). These are similar with the present study in Gombe metropolis.

          In this study, it was found that specialist hospital had the higher prevalence of plasmodium infection than the Federal medial centre Gombe. This may be due to excessive visits of malaria patients to specialist hospital than Federal Medial centre Gombe. Because of cost implication.

                     Also in this study, it was found that children between the ages of 1 and 3 years had the highest prevalence of plasmodium infections (table 3) compared with the other age groups. This may be due to the fact that at that age, their immunity to parasitic infections has not been fully developed. The prevalence of plasmodium infections has been found to reduce with other ages (4-6 and 7—10 years). The prevalence of parasitic infections among the different age groups in the present study was not significant (P< 0.05) indicating that the occurrences of these infections on these age groups were the same (table 3).

          The present study has shown that plasmodium infections were more common in the male than in the female subjects (Table 6). The present result conforms with the recorded higher prevalence of plasmodium infection in male than in female in these two hospitals in Gombe metropolis. However, studies have shown that females have better immunity to parasitic disease and this was attributed to genetic and hormonal factors (Krogstad, 1996).

          In this study, males of ages 1 — 3 years had the highest prevalence of malaria (table 10). This may have been attributed to their young ages. It has been reported that Plasmodiurn infection was more prevalent in young children because of their relatively less developed immune system.(Krogstad, 1996).

          In this study, there were results that show positive in rapid test kits method for plasmodium falciparum while they were negative in microscopic observation (Appendix 4). This finding indicated that children may have become infected again after treatment with the local drugs. It is also possible that the Plasmodium parasites may have developed resistance to some anti-malarial drugs like chloroquine.

          The elimination half life of Sulfadoxine (100 to 231 hours) and Pyrimethamine (54 to 148 hours), strongly favours re-infection than development of resistance. The possibilities of combining this drug with its useful therapeutic life have been reported (Krogstad 1996). The possible strategies for halting or reversing this trend include the temporary withdrawal of Sulfadoxine-Pyrimethamine drug, or combining it with other effective anti- malarial drugs, for example Amodiaquine and the Artemisinin derivatives (Krogstand, 1996).

          Community health care workers must take in to account, cost considerations and affordability in view of the poor economic status of rural communities where the drugs are mostly needed. The high prevalence recorded during follow-up investigation may also be an indication of re-infection rather than drug failure. This is because the life cycle of the malaria parasite is usually fourteen days. People who are using mosquito bed net will experience a lower prevalence (Krogstad, 1996).

Conclusion

          The high infection rate with Plasmodium falciparum causes great concern in this study and this was recognized through rapid test kits method.

          This study, therefore strongly suggest that hospital surveillance may be a useful tool in monitoring malaria disease and the result presented suggests that there should be completely mobilization and health education in order to:

i.       Reduce man-vector contact.

ii.      Reduce frequent of self medical and in complete prophylaxis

iii.  Encourage proper and prompt utilization of available health care facilities.

iv.  This high infection rate with Plasmodium falciparum causes great concern in population is indicative of active transmission i.e. the population is at high risk of malaria infection.

References

(CDC, 2000) Department of Health and Human Services, Centres for Disease Control and Prevention 2000.

 (FMOH) Federal Ministry of Health (1991). Malaria in Nigeria: Epidmiology and Control. Nigeria Bulletin of Epidemiology, 1(3): 1-19

CDC (2006) Malaria, anopheles mosquitoes (2006). Nigeria Journal of Malaria.

Allen, R. (2000). Ground — level action is vital in emergencies. WHO/RBM News. 1:2

Cheesbrough, M. (1992). District Laboratory Practice in Tropical countries. Part 1. Cambridge University Press. United Kingdom. 239 —258.

Culim, F. H. and Paskewite, S. M. (1995). Malaria: Current and Future Prospects for control. Annual Review of Entomology 40, 195 —219.

Curtis, C.F. ed. (1991). Control of Disease Vectors in the Community. Wolfe, London.

Eneanya, C.I., (1996). Seasonal variation in malaria episodes among Residents in Udi, a semi-urban community in southeast Nigeria. The Nigeria Journal of Parasitology. 19: 39—43.

Krongstad D. J. (1996). Malaria as a re-emerging disease epidemiolgy. Rev 18:77 —89

Matur, D. M. Azare, B.A. and Ugbong, L. (2001). prevalence of malaria parasites among undergraduate students of university of Abuja. The Nigeria Journal of Parasitology Vol. 22 (1 & 2)49—52.

Mbanugo, J. I. and Ejims, D. 0. (2000). Plasmodium Infections in children aged 0-5 Years in Awka Metropolis, Anambra State, Nigeria. Nigeria Journal of Parasitology. 21 : 55—59.

Molta, N. B., Watila I .M., Gadzama, N. M., Muhammed, K. K., Ameh, J. O. and Daniel, H. I. (1991). Chloroquine Therapy of Plasmodium falciparum in Damboa, Borno State. Annals of Borno. 8((9): 224 —230.

Umar, M. M. (2006). NCE thesis on Prevalence of Malaria in Gombe Local Government Area.

World Health Organization (2003). World Malaria Report. P. 15.