RESUMEN
Despite the recent advances in drug research, finding a safe, effective, and easy to use chemotherapy for human African trypanosomiasis (HAT) remains a challenging task. The four current anti-trypanosomiasis drugs have major disadvantages that limit more widespread use of these drugs in the endemic regions of sub-Saharan Africa. Pentamidine and suramin are limited by their effectiveness against the only first stage of Trypanosoma brucei gambiense and Trypanosoma brucei rhodesiense, respectively. In addition, melarsoprol and eflornithine (two second stage drugs) each have disadvantages of their own. The former is toxic and has increasing treatment failures while the latter is expensive, laborious to administer, and lacks efficacy against T. b. rhodesiense. Furthermore, melarsoprol's toxicity and decreasing efficacy are glaring problems and phasing out the drug as a frontline treatment against T. b. gambiense is now possible with the emergence of competent, safe combination chemotherapies such as nifurtimox-eflornithine combination treatment (NECT). The future of eflornithine, on the other hand, is more promising. The drug is useful in the context of combination chemotherapy and potential orally administered analogues. Due to the limits of monotherapies, greater emphasis should be placed on the research and development of combination chemotherapies, based on the successful clinical tests with NECT and its current use as a frontline anti-trypanosomiasis treatment. This review discussed the current and future chemotherapy strategies for the treatment of HAT.
Asunto(s)
Antiprotozoarios/uso terapéutico , Tripanosomiasis Africana/tratamiento farmacológico , África/epidemiología , Antiprotozoarios/efectos adversos , Resistencia a Medicamentos , Quimioterapia/métodos , Quimioterapia Combinada/métodos , Humanos , Trypanosoma brucei gambiense/efectos de los fármacos , Trypanosoma brucei rhodesiense/efectos de los fármacos , Tripanosomiasis Africana/epidemiologíaRESUMEN
Blastocystis is a common intestinal micro-eukaryote found in both humans and non-human hosts and known to be genetically very diverse. It has been divided into numerous subtypes (STs), nine of which have been identified in humans to date. Surveys of ST prevalence have started to emerge over the past few years but to date no data are available for any African country except Egypt and Tanzania. In this study, we determined the prevalence of Blastocystis STs in populations from Libya, Liberia and Nigeria, as well as expanding the dataset available for the UK. A total of 356 Blastocystis STs were identified in this study, 271 from the UK, 38 from Libya, 25 from Liberia and 22 from Nigeria. SSU rRNA gene sequences revealed the presence of eight of the nine STs known from humans but at varying frequencies between countries. ST1 was the most common ST in Libya and Nigeria whereas ST3 showed the highest frequency in the other two countries, as indeed is the case in most populations around the world. ST4 was absent in Libya and ST2 in Nigeria, while no ST5, ST6, ST8 or ST9 infections were detected in any of the three African populations. The picture emerging from this and other surveys suggests that there is significant variation in ST prevalence between populations. Some of the possible reasons for and implications of this diversity are discussed.
Asunto(s)
Infecciones por Blastocystis/parasitología , Blastocystis/clasificación , Blastocystis/genética , Variación Genética , Filogeografía , Adolescente , Adulto , África/epidemiología , Blastocystis/aislamiento & purificación , Infecciones por Blastocystis/epidemiología , Niño , ADN Protozoario/química , ADN Protozoario/genética , ADN Ribosómico/química , ADN Ribosómico/genética , Femenino , Genotipo , Humanos , Masculino , Epidemiología Molecular , Prevalencia , ARN Ribosómico 18S/genética , Reino Unido/epidemiología , Adulto JovenRESUMEN
BACKGROUND: Intestinal parasites are endemic in many parts of the world where HIV infection is also widespread. Previous studies had shown that the spectrum of opportunistic and common endemic parasitic infections with HIV vary in different regions and usually reflect the infections prevalent in these regions. This present study was aimed at comparing the prevalence and types of intestinal parasitic infections in HIV sero-positive and sero-negative patients in Lagos. MATERIALS AND METHODS: Venous blood and stool samples of 1080 patients, recruited from three health care institutions were screened for HIV infection and intestinal parasites using HIV-1, HIV-2 rapid tests, direct wet mount with saline/iodine and formol-ether technique, respectively. RESULTS: Results showed that 6% (65/1080) of patients were sero-positive for HIV infection. In addition, 23.3% (252/1080) patients were infected with intestinal parasites and 33.8% (22/65) of patients with HIV had intestinal parasites co-infections. The prevalence of Entamoeba histolytica/Entamoeba dispar, Entamoeba coli, Iodamoeba butschilii, Giardia intestinalis, and Hookworm were statistically significantly higher among HIV sero-positive patients as compared to the HIV sero-negative patients. In addition, HIV sero-positive patients had higher odds of mixed intestinal parasites than the HIV sero-negative patients (9.1% versus 3.9%; adjusted OR 2.05, 95% CI, 1.14-3.72, P=0.021). CONCLUSION: In this study population, HIV sero-positive patients were more likely to have intestinal parasitic infections. The study underscores the public health significance of intestinal parasitic infections in HIV infected individuals.
Asunto(s)
Infecciones por VIH/complicaciones , Parasitosis Intestinales/epidemiología , Parasitosis Intestinales/parasitología , Adolescente , Adulto , Archamoebae/clasificación , Archamoebae/aislamiento & purificación , Niño , Preescolar , Estudios Transversales , Entamoeba/clasificación , Entamoeba/aislamiento & purificación , Heces/parasitología , Femenino , Giardia/clasificación , Giardia/aislamiento & purificación , Humanos , Masculino , Persona de Mediana Edad , Nigeria/epidemiología , Prevalencia , Adulto JovenRESUMEN
The immune system is a highly evolved network of cells and molecules that can distinguish between invading pathogens and the body's own cells. But helminths, in their complex forms, are capable of down-regulating host immunity, protecting them from being eliminated and also minimizing severe pathology in the host. This review focuses on Strongyloides stercoralis and the immune responses in immunocompetent and/or immunocompromised individuals. It also highlights the implications for diagnosis/treatment and draws attention to an emerging public health disease. The solution to reducing the prevalence of strongyloidiasis remains on the effectiveness of pre-emptive measures in endemic communities, increased awareness, prompt early diagnosis as well as timely treatment.
Asunto(s)
Strongyloides stercoralis/inmunología , Estrongiloidiasis/inmunología , Animales , Humanos , Inmunocompetencia , Huésped Inmunocomprometido , Strongyloides stercoralis/patogenicidad , Estrongiloidiasis/parasitologíaRESUMEN
Dracunculiasis is a preventable parasitic disease that for many years has affected poor communities without a safe portable water supply. Transmission is basically limited among the nomadic in remote rural settings. Most countries, including Asia, are declared free from the Guinea worm disease restraining the burden of transmission to Africa especially Sudan, Ghana, Mali, Nigeria and Niger. This review focuses mainly on the progress made so far by the Global Guinea Worm Eradication Programme championed by the Carter Center, Centers for Disease Control and Prevention, World Health Organisation, The United Nations Children's Fund and the individual efforts of endemic nations through their National Guinea Worm Eradication Programme aimed towards total global Guinea worm eradication.
Asunto(s)
Dracunculiasis/prevención & control , África del Sur del Sahara/epidemiología , Animales , Dracunculiasis/epidemiología , Dracunculiasis/transmisión , Dracunculus/parasitología , Dracunculus/patogenicidad , HumanosRESUMEN
BACKGROUND: Chloroquine (CQ) has been in use in Africa for a long time. Because of misuse, this drug has now lost its efficacy due to the emergence of resistance strains in most parts of Africa. Recently, it was shown that after chloroquine has been withdrawn from the market, chloroquine-sensitive Plasmodium falciparum re-emerged and chloroquine could again be used successfully as an antimalarial. Surveillance of parasite populations is, therefore, important to decide whether chloroquine could be re-introduced. METHODS: To estimate the prevalence of the most pivotal polymorphisms, including Pfcrt K76T, Pfmdr1 N86Y and Pfmdr1 Y184F mutations, and their contributions to the outcome of CQ treatment, isolates from Osogbo Western Nigeria were tested using the Fluorescence Resonance Energy Transfer (FRET) method on a real-time PCR instrument. RESULTS: 116 children with acute uncomplicated P. falciparum malaria infections were treated with the standard dosage of CQ and followed-up for 28 days. Blood samples were collected on filter paper at enrollment and during follow-up for identification of parasite carrying the chloroquine resistant transporter (pfcrt) and P. falciparum-multi drug resistance (pfmdr1) gene mutations. Parasitological assessment of response to treatment showed that 62% of the patients were cured and 38% failed the CQ treatment. The presence of single mutant pfcrt (T76) alleles (P = 0.003) and in combination with mutant pfmdr1 Y86 (P = 0.028) was significantly associated with in vivo CQR. No other mutation on its own or in combinations was significantly associated with treatment outcome. Mutant pfcrt was more prevalent in both pre- and post-treatment isolates. No association was observed between age or initial level of parasitaemia and chloroquine treatment outcome. CONCLUSION: The result established the usefulness and accuracy of real time PCR in pfcrt and pfmdr1 mutation detection and also give further evidence to the reliability of the pfcrt T76 point mutation as a molecular marker for CQ resistance.