Chemoprophylaxis of Onchocerca infections: in a controlled, prospective study ivermectin prevents calves becoming infected with O. ochengi

Parasitology ◽  
1999 ◽  
Vol 118 (2) ◽  
pp. 195-199 ◽  
Author(s):  
V. L. TCHAKOUTÉ ◽  
M. BRONSVOORT ◽  
V. TANYA ◽  
A. RENZ ◽  
A. J. TREES
Keyword(s):  
Public Health ◽  
West Africa ◽  
Prospective Study ◽  
Adult Worm ◽  
Control Strategies ◽  
Onchocerca Volvulus ◽  
River Blindness ◽  
Public Health Importance ◽  
Therapeutic Benefits ◽  
Northern Cameroon

Onchocerciasis (‘River Blindness’), caused by the filarial nematode Onchocerca volvulus is of major public health importance in West Africa. Ivermectin, a drug originally developed for veterinary use, is now being incorporated in control strategies but whilst it has potent efficacy against L1 larvae (microfilariae), ivermectin is not lethal to adult (L5) O. volvulus, nor to adults of the related cattle parasite O. ochengi. We have exploited this model to determine if ivermectin has prophylactic activity against naturally transmitted, O. ochengi infections in a controlled, prospective study in northern Cameroon. Calves were treated monthly with ivermectin at either 200 μg/kg or 500 μg/kg for 21 months. None of 15 treated calves developed adult worm infection, whereas 5/6 untreated controls became infected (P<0·001) with a total of 54 O. ochengi nodules, and all 5 developed patent microfilaridermia. These results have significant implications for the use of ivermectin in humans, and suggest that strategic chemotherapy at times of maximal transmission will confer prophylactic as well as therapeutic benefits.

scholarly journals The Threat of Ebola Virus Disease: a Call to Integrate all Sectors in Surveillance Activities in Ghana

2015 ◽  
Vol 7 (1) ◽  
Author(s):  
Dennis O. Laryea ◽  
Yaw Amoako ◽  
Dan V. Armooh ◽  
Emmanuel P. Abbeyquaye ◽  
Bernice N. Amartey
Keyword(s):  
Public Health ◽  
Health Service ◽  
West Africa ◽  
Health System ◽  
Disease Surveillance ◽  
Ebola Virus ◽  
Virus Disease ◽  
Public Health Importance ◽  
Ghana Health ◽  
Ghana Health Service

Surveillance for communicable diseases of public health importance is critical in preventing and controlling outbreaks. In Ghana, this responsibility lies with the Disease Surveillance Department of the Ghana Health Service (GHS). However, the structure of Ghana's health system means surveillance activities by the department are concentrated in GHS facilities. Active surveillance in non-GHS facilities usually occur during outbreaks. In light of the recent Ebola outbreak in West Africa, there is the need to integrate the surveillance activities to include all health facilities to ensure the prompt identification of cases.

scholarly journals Beginning of the end of Onchocerciasis in the Americas

2013 ◽  
pp. 132-133
Author(s):  
Gloria Ines Palma ◽  
Sofía Duque Bernal ◽  
Ruben Santiago Nicholls
Keyword(s):  
West Africa ◽  
20Th Century ◽  
Slave Trade ◽  
Onchocerca Volvulus ◽  
Parasitic Disease ◽  
Black Flies ◽  
River Blindness ◽  
Vector Borne ◽  
Single Focus ◽  
Transmission Foci

Onchocerciasis, also known as River Blindness, is a parasitic disease caused by the nematode Onchocerca volvulus and transmitted by black flies of the genus Simulium. It is endemic in Africa, where an estimated 37 million people are infected. It is almost certain that the slave trade in the 17th and 18th centuries brought onchocerciasis from West Africa to the Americas (1), where transmission foci where established in six countries: Mexico, Guatemala, Venezuela, Brazil, Ecuador and Colombia. Since the beginning of the 20th century it was suspected that this vector borne disease was present in Colombia but the first confirmed case was not reported until 1965. The exact location of the single focus in the country was confirmed almost thirty years later in the locality of Naicioná, on the stream that bears the same name

scholarly journals Population biology of human onchocerciasis

1999 ◽  
Vol 354 (1384) ◽  
pp. 809-826 ◽  
Author(s):  
María-Gloria Basáñez ◽  
Michel Boussinesq
Keyword(s):  
West Africa ◽  
Population Biology ◽  
Control Programme ◽  
Infection Prevalence ◽  
Mathematical Framework ◽  
River Blindness ◽  
Control Programmes ◽  
Elimination Programme ◽  
Northern Cameroon ◽  
Onchocerciasis Control

Human onchocerciasis (river blindness) is the filarial infection caused by Onchocerca volvulus and transmitted among people through the bites of the Simulium vector. Some 86 million people around the world are at risk of acquiring the nematode, with 18 million people infected and 600 000 visually impaired, half of them partially or totally blind. 99% of cases occur in tropical Africa; scattered foci exist in Latin America. Until recently control programmes, in operation since 1975, have consisted of antivectorial measures. With the introduction of ivermectin in 1988, safe and effective chemotherapy is now available. With the original Onchocerciasis Control Programme of West Africa coming to an end, both the new African Programme for Onchocerciasis Control and the Onchocerciasis Elimination Programme for the Americas, rely heavily on ivermectin self–sustained mass delivery. In consequence, the need for understanding the processes regulating parasite abundance in human and simuliid populations is of utmost importance. We present a simple mathematical framework built around recent analyses of exposure– and density–dependent processes operating, respectively, within the human and vector hosts. An expression for the basic reproductive ratio, R 0 , is derived and related to the minimum vector density required for parasite persistence in localities of West Africa in general and northern Cameroon in particular. Model outputs suggest that constraints acting against parasite establishment in both humans and vectors are necessary to reproduce field observations, but those in humans may not fully protect against reinfection. Analyses of host age–profiles of infection prevalence, intensity, and aggregation for increasing levels of endemicity and intensity of transmission in the Vina valley of northern Cameroon are in agreement with these results and discussed in light of novel work on onchocerciasis immunology.

scholarly journals Bacteriome diversity of blackflies gut and association with Onchocerca volvulus, the causative agent of onchocerciasis in Mbam valley (Center Region, Cameroon)

2020 ◽  
Author(s):  
Arnauld Efon-Ekangouo ◽  
Hugues Nana-Djeunga ◽  
Guilhem Sempere ◽  
Joseph Kamgno ◽  
Flobert Njiokou ◽  
...  
Keyword(s):  
Vector Control ◽  
Bacterial Communities ◽  
Control Strategies ◽  
Onchocerca Volvulus ◽  
Parasitic Infections ◽  
Tsetse Flies ◽  
Protective Effects ◽  
River Blindness ◽  
Parasite Infestation

AbstractBackgroundVector control using larvicides is the main alternative strategy to address limits of preventive chemotherapy using ivermectin to fight onchocerciasis. However, it remains substantially limited by implementation difficulties, ecological concerns and resistance of vector populations. Therefore, efficient and environmentally safe alternative control strategies are still needed. This study explores the role of blackfly bacterial communities both on vector competence and refractoriness to O. volvulus infection in order to determine their potential as a novel vector control-based approach to fight onchocerciasis.Principal findingsA total of 1,270 blackflies were dissected and the infection rate was 10.1%, indicative of ongoing transmission of onchocerciasis in the surveyed communities. Sequencing process revealed 19 phyla and 210 genera, highlighting the diversity of gut blackflies bacterial communities. Wolbachia was the predominant genus with 70% of relative abundance of blackflies gut bacterial communities. Serratia sp and Acidomonas genera were significantly abundant among infected blackflies (p=0.043 and p=0.027, respectively), whereas other genera as Brevibacterium were associated with the absence of infection (p=0.008).Conclusion/SignificanceThis study revealed that blackfly native bacteria are potentially involved in infection by O. volvulus, either by facilitating or preventing the parasite infestation of the vector. These bacteria represent an interesting potential as a biological target for a novel approach of vector control to fight onchocerciasis.Author summaryStudies of arthropods involved in vector-borne diseases (tsetse flies, mosquitoes, and drosophila) demonstrated the importance of their native bacteria either to ease infection and transmission of human pathogenic microorganisms including parasites or on the contrary to induce host protective effects against these parasites. Indeed, some native bacteria of arthropod vectors are now recognized to be associated either with the resistance of their hosts to parasitic infections, or the reduction of their host’s viability in case of the parasite infestation, thus highlighting the potential of such bacteria to be used as biological tool for vector control strategies. However, such bacteria have never been described on blackfly, an arthropod transmitting Onchocerca volvulus, which is the parasite responsible of onchocerciasis commonly known as river blindness. This study aimed to fill this gap by investigating the bacterial diversity of blackfly bacteriome and describing the possible role of bacteria communities in susceptibility/resistance features of the blackflies to O. volvulus infection, and therefore their potential as biological targets or tool for vector control. The screening of these blackflies’ native bacteria during this study, highlighted some bacteria genera of interest with significant association either with the absence of O. volvulus in blackfly or with vector infection.

scholarly journals Strategies for Suppression and Elimination of Onchocerciasis in Endemic Countries: A Review of the Literature

2021 ◽  
pp. 26-35
Author(s):  
Michael O. Elom ◽  
Ifeoma A. Okpara-Elom
Keyword(s):  
Public Health ◽  
Neglected Tropical Diseases ◽  
Control Measure ◽  
Relevant Literature ◽  
Drug Distribution ◽  
Public Health Problem ◽  
River Blindness ◽  
African Countries ◽  
Public Health Importance ◽  
Preventive Chemotherapy

Onchocerciasis is one of the neglected tropical diseases with great public health importance in the Americas and in many African countries. River blindness, can lead to severe dermatologic and ophthalmologic complications that may terminate in blindness and other associated social stigmatizations. Preventive chemotherapy with the use of annual mass drug administration with ivermectin (Mectizan®) has been the only sustainable management and control measure of the disease in Africa, though with limited efficacy. Based on those limitations, there is doubt that suppression and elimination of the disease targeted to take place in 2020 and 2025 respectively may be actualized. The aim of the review is to update knowledge on existing strategies relevant to achieving suppression and probable elimination of onchocerciasis in endemic countries and to highlight identified obstacles militating against such strategies. Review of past and recently published relevant literature on the topic was carried out using electronic databases such as Google scholar. For feasible suppression and elimination in the stipulated years, some strategies may have to be carried out. The suggested strategies include incorporation of insecticides with chemotherapy, adoption of semi-annually or quarterly ivermectin in-take compliance, inclusion of every member of endemic communities in treatment, avoidance of interruption in drug distribution, correction of misconception of onchocerciasis and use of gold standard diagnostic techniques. With adherence to the suggested strategies of control, the story of onchocerciasis as a public health problem would become a history and the disease could be elimination in all transmission foci.

Alpha proteobacteria of genusAnaplasma(Rickettsiales: Anaplasmataceae): Epidemiology and characteristics ofAnaplasmaspecies related to veterinary and public health importance

Parasitology ◽  
2016 ◽  
Vol 143 (6) ◽  
pp. 659-685 ◽  
Author(s):  
FARHAN AHMAD ATIF
Keyword(s):  
Public Health ◽  
Control Strategies ◽  
Age Groups ◽  
Geographic Area ◽  
Cross Reactivity ◽  
Control Measures ◽  
Habitat Modification ◽  
Nucleic Acid Detection ◽  
Public Health Importance ◽  
Granulocytic Anaplasmosis

SUMMARYTheAnaplasmaspecies are important globally distributed tick-transmitted bacteria of veterinary and public health importance. These pathogens, cause anaplasmosis in domestic and wild animal species including humans.Rhipicephalus, Ixodes, DermacentorandAmblyommagenera of ticks are the important vectors ofAnaplasma.Acute anaplasmosis is usually diagnosed upon blood smear examination followed by antibodies and nucleic acid detection. All age groups are susceptible but prevalence increases with age. Serological cross-reactivity is one of the important issues amongAnaplasmaspecies. They co-exist and concurrent infections occur in animals and ticks in same geographic area. These are closely related bacteria and share various common attributes which should be considered while developing vaccines and diagnostic assays. Movement of susceptible animals from non-endemic to endemic regions is the major risk factor of bovine/ovine anaplasmosis and tick-borne fever. Tetracyclines are currently available drugs for clearance of infection and treatment in humans and animals. Worldwide vaccine is not yet available. Identification, elimination of reservoirs, vector control (chemical and biological), endemic stability, habitat modification, rearing of tick resistant breeds, chemotherapy and tick vaccination are major control measures of animal anaplasmosis. Identification of reservoirs and minimizing the high-risk tick exposure activities are important control strategies for human granulocytic anaplasmosis.

An Overview of Gambling in India

2020 ◽  
Vol 15 ◽  
pp. 4
Author(s):  
Sanju George ◽  
Jessy Fenn ◽  
Kripa Robonderdeep
Keyword(s):  
Public Health ◽  
Public Health Importance ◽  
The World

Gambling is a popular pastime in India, as in most cultures across the world. Although research from India is limited, there is enough evidence to suggest that it should be of public health importance. In this brief paper, we look at the evolution of gambling in India and also discuss potential ways forward to address this issue.

scholarly journals Reconciling Epidemiology’s Aspirations and Capabilities

2020 ◽  
Author(s):  
David A Savitz
Keyword(s):  
Public Health ◽  
Epidemiologic Studies ◽  
Public Health Importance ◽  
Public Health Action ◽  
Action Current ◽  
Current Trends ◽  
The Face ◽  
Health Action ◽  
New Challenges ◽  
Health Applications

Abstract Interpreting the results of epidemiologic studies calls for objectivity and rigorous scrutiny, acknowledging the limitations that temper the applicability of the findings to public health action. Current trends have posed new challenges to balancing goal of scientific objectivity and validity with public health applications. The ongoing tension between epidemiology’s aspirations and capability has several sources: the need to overpromise in research proposals, compromising methodologic rigor because of public health importance, defending findings in the face of hostile critics, and appealing to core constituencies who have specific expectations from the research.

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