Transboundary nomadic population movement: a potential for import-export of poliovirus.

BACKGROUND: Nomadic populations have a considerably higher risk of contracting a number of diseases but, despite the magnitude of the public health risks involved, they are mostly underserved with few health policies or plans to target them. Nomadic population movements are shown to be a niche for the transmission of diseases, including poliomyelitis. The nomadic routes traverse the northern states of Nigeria to other countries in the Lake Chad subregion. As part of the February 2016 polio supplemental immunization activity (SIA) plans in Bauchi state, a review of nomadic routes and populations identified a nomadic population who originated from outside the international borders of Nigeria. This study describes the engagement process for a transboundary nomadic population and the interventions provided to improve population immunity among them while traversing through Nigeria. METHODS: This was an intervention study which involved a cross-sectional mixed-method (quantitative and qualitative) survey. Information was collected on the nomadic pastoralists entry and exit points, resting points, and health-seeking behavior using key informant interviews and semistructured questionnaire. Transit vaccination teams targeted the groups with oral polio vaccines (OPVs) and other routine antigens along identified routes during the months of February to April 2016. Mobile health teams provided immunization and other child and maternal health survival interventions. RESULTS: A total of 2015 children aged under 5 years were vaccinated with OPV, of which 264 (13.1%) were zero-dose during the February 2016 SIAs while, in the March immunization plus days (IPDs), 1864 were immunized of which 211 (11.0%) were zero-dose. A total of 296 children aged under 1 year old were given the first dose of pentavalent vaccine (penta 1), while 119 received the third dose (penta 3), giving a dropout rate of 59.8%. CONCLUSIONS: Nomadic pastoralists move across international borders and there is a need for transboundary policies among the countries in the Lake Chad region to improve population immunity and disease surveillance through a holistic approach using the One-health concept.

Hb O-Tibesti [beta121(GH4)Glu-->Lys; beta11(A8)Val-->Ile], a hemoglobin variant carrying in the same beta chain the substitutions of Hb O-Arab and Hb Hamilton, found in combination with Hb S [beta6(A3)Glu-->Val].

Hb O-Tibesti, carries in the same chain the substitution of Hb O-Arab [beta121(GH4)Glu-->Lys] and that of Hb Hamilton [beta11(A8)Val-->Ile]. Hb O-Tibesti may be distinguished from Hb O-Arab by polyacrylamide gel electrophoresis in the presence of urea and Triton-X100, and by reversed phase high performance liquid chromatography. It was found in a compound heterozygous condition with Hb S [beta6(A3)Glu-->Val] in a child of Chad-Sudanese descent, suffering from a sickle cell syndrome. Compared to the classical description of the Hb S/Hb O-Arab association, the additional Hb Hamilton mutation does not seem to modify the clinical presentation.

[Study of the transmission of onchocerciasis in the surroundings of a refugee camp located in the savanna zone of Cameroon]. / Etude de la transmission de l'onchocercose aux alentours d'un camp de réfugiés situé en zone de savane du Cameroun.

Chadian refugees, most of whom are free from onchocerciasis, settled recently in a camp in a savanna area of the northern Cameroon where the prevalence is about 80% and the blindness rate is 4% of the adult population. In view of the risks of onchocerciasis facing the immigrants, the authors carried out an entomological survey in this region aimed at determining the modes of transmission and assessing the possibilities for the control of this disease. After a three-month survey in the study area, it appears clearly that 1) transmission takes place only during the rainy season, 2) the main vectors are the two savanna species, Simulium damnosum s.s. and Simulium sirbanum, 3) the larval breeding sites are not located on the principal river, the Faro, but on its small seasonal tributaries, 4) the local populations still free from onchocerciasis and the Chadian refugees who farm close to these tributaries run the risk of getting serious ocular lesions in the long run which could lead to blindness. The conclusions of this survey prompted the authors to envisage an onchocerciasis control campaign in this area against the larval stages of the vectors.

[Campaign against the vectors of onchocerciasis in the surroundings of a refugee camp located in a savanna zone of Cameroon]. / Lutte contre les vecteurs de l'onchocercose aux alentours d'un camp de réfugiés situé en zone de savane du Cameroun.

In view of the risks of onchocerciasis facing Chadian refugees who have settled in a camp in a savanna hyperendemic area of northern Cameroon, the authors concluded that a vector control directed against the black fly larvae located on small seasonal tributaries of the main water course of this area should be carried out during the four to five months of the rainy season, i.e., during the whole period of transmission of this disease. The operations were undertaken during two consecutive rainy seasons. The first year consisted in developing ground-based control techniques and evaluating the larvicidal efficacy at the larval level. The second year was, particularly, devoted to the study of the impact of the vector control on the biting rate and on the transmission of onchocerciasis. Every week, three of the tributaries close to the camp were treated with an Emulsifiable Concentrate of temephos. Throughout the rainy season, the larvicide eliminated almost all the pre-adult black fly stages on these water courses. At the point in a high onchocercal endemicity area, it also reduced the biting rate by 60% and the Annual Transmission Potential by 72%, i.e., to values corresponding to the lower meso-endemicity threshold. Since these results were obtained at a very unfavourable point from the standpoint of black fly density and onchocerciasis transmission, the authors consider that vector control carried out under these conditions protects the local populations and the Chadian refugees effectively from black fly bites and a risk of severe onchocerciasis.

[Serodiagnosis of malaria (author's transl)]. / Zur Serodiagnostik der Malaria

Homologous and heterologous malaria pathogens were used as antigens for the determination of malaria antibodies by indirect immunofluorescence. Homologous antibodies fell in the second half year, after successful treatment, down to the limit of demonstrability. In inhabitants of endemic malarial areas, who lived in the German Federal Republic, signs of a fall in antibodies could be observed after about 30 months. The predominance of particular malaria pathogens of the country of origin was recognizable in the antibody spectrum of these persons. Malaria antibody findings of three comparable groups of exposed persons under chemoprophylaxis ought to provide pointers to the parasitemias which had occurred and which were held responsible for the antibody production. Persons without chemoprophylaxis from malarial areas served as controls. The markedly deviating results of the antibody findings in the serum donors can only be explained by more seldom parasitemias in persons with adequate chemoprophylaxis.