The Use of Broadly Neutralizing Antibodies (bNAbs) in HIV-1 Treatment and Prevention.

BACKGROUND: Although antiretroviral therapy (ART) effectively halts disease progression in HIV infection, the complete eradication of the virus remains elusive. Additionally, challenges such as long-term ART toxicity, drug resistance, and the demanding regimen of daily and lifelong adherence required by ART highlight the imperative need for alternative therapeutic and preventative approaches. In recent years, broadly neutralizing antibodies (bNAbs) have emerged as promising candidates, offering potential for therapeutic, preventative, and possibly curative interventions against HIV infection. OBJECTIVE: This review aims to provide a comprehensive overview of the current state of knowledge regarding the passive immunization of bNAbs in HIV-1-infected individuals. MAIN FINDINGS: Recent findings from clinical trials have highlighted the potential of bNAbs in the treatment, prevention, and quest for an HIV-1 cure. While monotherapy with a single bNAb is insufficient in maintaining viral suppression and preventing viral escape, ultimately leading to viral rebound, combination therapy with potent, non-overlapping epitope-targeting bNAbs have demonstrated prolonged viral suppression and delayed time to rebound by effectively restricting the emergence of escape mutations, albeit largely in individuals with bNAb-sensitive strains. Additionally, passive immunization with bNAb has provided a "proof of concept" for antibody-mediated prevention against HIV-1 acquisition, although complete prevention has not been obtained. Therefore, further research on the use of bNAbs in HIV-1 treatment and prevention remains imperative.

Life expectancy among patients with pulmonary tuberculosis is less than one-third of life expectancy in the background population in Guinea-Bissau-an observational study.

BACKGROUND: Few studies have assessed life expectancy of patients with tuberculosis (TB) against a comparable background population, particularly in low-income, high-incidence settings. This study aimed to estimate the life expectancy (LE) of patients with TB in the West African country of Guinea-Bissau and compare it with the LE of the background population. METHODS: This study used data from the Bandim TB cohort from 2004-20 as well as census data from the capital of Guinea-Bissau. LE was estimated using a bootstrapped Kaplan-Meier survival analysis for patients with TB and the background population, stratifying by age of entry and various patient subgroups. The analysis was further stratified by diagnosis period and length of schooling (an indicator of socioeconomic status), to assess their influence on LE. A sensitivity analysis was performed assuming death at loss to follow-up. RESULTS: The analysis included 2278 patients and a background population of 169 760 individuals. Overall median LE among 30-year-old patients with TB was 10.7 years (95% CI: 8.7-12.6), compared with 35.8 (95% CI: 35.1-36.5) in the background population. LE was shorter in HIV-infected patients and those who had unsuccessful treatment outcome; however, even among those who were both uninfected with HIV and experienced successful treatment outcome, LE was 20% shorter than in the background population. Longer schooling appeared to decrease mortality. CONCLUSIONS: TB substantially shortens LE. This effect is present even in patients who are uninfected with HIV and who have successful treatment outcome.

The HIV care continuum of Guinea-Bissau; Progress towards the UNAIDS 90-90-90 targets for HIV-1 and HIV-2.

OBJECTIVE: In the 2020 UNAIDS HIV treatment goals, 90% of people living with HIV (PLHIV) should be diagnosed, 90% of these should receive antiretroviral treatment (ART) and 90% of these should be virally suppressed. We aimed to evaluate whether Guinea-Bissau fulfills the 2020 treatment goals for both for HIV-1 and HIV-2. DESIGN: By combining data from a general population survey, treatment records from HIV clinics across Guinea-Bissau and a biobank from patients attending the largest HIV clinics in Bissau, we estimated each column of the 90-90-90 cascade. METHOD: 2601 participated in the survey and were used to estimate the proportion of PLHIV who knew their HIV status and the proportion of PLHIV on ART. Answers given in the survey was verified with treatment records from HIV clinics. We measured viral load from biobank materials from HIV patients and estimated the proportion of virally suppressed PLHIV. RESULT: 19.1% of PLHIV indicated to be aware of their HIV status. Of these, 48.5% received ART, and 76.4% of these were virally suppressed. For HIV-1 and HIV-1/2 the results were 21.2%, 40.9% and 75.1%. For HIV-2 the results were 15.9%, 63.6% and 80.7%. 26.9% of all HIV-1 infected in the survey were virologically suppressed, indicating that a much higher number of HIV-1 infected were aware of their status and on treatment. CONCLUSION: Guinea-Bissau lags severely behind both the global and regional progress. Improvement in both testing and treating HIV is necessary to improve the quality of care.

Xpert MTB/RIF on urine samples to increase diagnosis of TB in people living with HIV in Guinea-Bissau.

OBJECTIVES: We investigated if Xpert MTB/RIF (Xpert) testing on urine samples among newly diagnosed HIV-patients as an adjunctive test to Xpert testing on sputum increases diagnosis. We sought to define subgroups of patients, for whom testing with either test is especially advantageous. METHODS: We included patients >15 years, newly diagnosed with HIV, that delivered a urine sample on the day of HIV-diagnosis at the biggest HIV-clinic in Guinea-Bissau between September 5, 2016 and October 13, 2017 into a cross-sectional study. Patients were asked for a sputum sample, which was Xpert tested if returned within 30 days. A questionnaire and physical examination were completed on day of inclusion. RESULTS: We included 390 patients. TB prevalence was 12.6%. Adding Xpert urine test to all newly diagnosed HIV-patients increased diagnostic yield of TB by 58% compared with testing on sputum alone. Patients who tested positive by Xpert on urine samples were clinically similar to those tested with sputum, except that the sputum positives reported more cough (p=0.03). CONCLUSIONS: Indiscriminate Xpert urine testing in newly diagnosed HIV-patients with advanced disease increased diagnostic yield. Xpert testing for TB on urine and sputum should be offered as screening in Guinea-Bissau and possibly in similar settings.

Long-term detection of SARS-CoV-2 antibodies after infection and risk of re-infection.

OBJECTIVES: To evaluate long-term sensitivity for detection of total antibodies against SARS-CoV-2 METHODS: From week 41, 2020, through week 26, 2021, all Danish blood donations were tested for SARS-CoV-2 antibodies with the Wantai assay. The results were linked with polymerase chain reaction (PCR) test results from the Danish Microbiological Database (MiBa). RESULTS: During the study period, 105,646 non-vaccinated Danish blood donors were tested for SARS-CoV-2 antibodies, and 3,806 (3.6%) had a positive PCR test before the blood donation. Among the donors with a positive PCR test, 94.2% subsequently also had a positive antibody test. The time between the positive PCR test and the antibody test was up to 15 months and there was no evidence of a decline in proportion with detectable antibodies over time. A negative serological result test was associated with a higher incidence of re-infection (Incidence Rate Ratio = 0.102 (95% confidence interval (CI): 0.039-0.262)). CONCLUSION: Among healthy blood donors, 94.2% developed SARS-CoV-2 antibodies after infection, and a lack of detectable antibodies was associated with re-infection.

Mother-to-child HIV-2 transmission: comparison with HIV-1 and evaluation of factors influencing the rate of transmission. A systematic review.

A review and collection of data on HIV-2 mother-to-child transmission (MTCT) is absent in the literature. This systematic review and meta-analysis aims to provide a pooled estimate of the rate of HIV-2 MTCT and to identify factors influencing the rate of transmission. PubMed and EMBASE were used to identify eligible publications using a sensitive search strategy. All publications until February 2021 were considered; 146 full-text articles were assessed. Observational studies describing the rate of HIV-2 MTCT in a defined HIV-2 infected study population were included. Other publication types and studies describing HIV-1 or dually infected populations were excluded. Nine studies consisting of 901 mother-child pairs in West Africa, France and Portugal were included in the meta-analysis. The pooled rate estimate of HIV-2 MTCT for antiretroviral therapy-naïve women was 0.2% (95% CI 0.03 to 1.47%), considerably lower than that for HIV-1. The levels of maternal HIV RNA and CD4 cell count were positively related to the vertical transmission rate. Maternal HIV-2 infection did not significantly affect perinatal mortality. It was concluded that the vertical transmission of HIV-2 is lower than that of HIV-1. Maternal viral load and CD4 cell count appear to influence the rate of HIV-2 MTCT.

Reactive arthritis after COVID-19.

A previously healthy 53-year-old man was hospitalised for 12 days due to COVID-19 with shortness of breath. A few days after discharge from hospital, the patient developed fever and severe pain in several joints in the lower extremities. The pain was so severe that the patient was unable to stand on his feet. Synovial fluid from the right-side knee contained a high number of polynuclear cells and a few mononuclear cells. Microscopy, culture and PCR tests for bacterial infection were all negative. Furthermore, the patient tested negative for rheumatoid factor, anti-cyclic citrullinated peptide and human leukocyte antigen (HLA)-B27. Thus, the condition was compatible with reactive arthritis. The condition improved markedly after a few days' treatment with non-steroid anti-inflammatory drugs and prednisolone.

Life expectancy of HIV-infected patients followed at the largest hospital in Guinea-Bissau is one-fourth of life expectancy of the background population.

PURPOSE: To estimate the life expectancy (LE) of HIV-infected patients in the West African country Guinea-Bissau and compare it with the background population. METHODS: Using data from the largest HIV outpatient clinic at the Hospital Nacional Simão Mendes in the capital Bissau, a retrospective observational cohort study was performed. The study included patients attending the clinic between June 2005 and January 2018. A total of 8958 HIV-infected patients were included. In the analysis of the background population, a total of 109,191 people were included. LE incorporating loss to follow-up (LTFU) was estimated via Kaplan-Meier estimators using observational data on adult HIV-infected patients and background population. RESULTS: The LE of 20-year-old HIV-infected patients was 9.8 years (95% CI 8.3-11.5), corresponding to 22.3% (95% CI 18.5-26.7%) of the LE of the background population. (LE for 20-year-olds in the background population was 44.0 years [95% CI 43.0-44.9].) Patients diagnosed with CD4 cell counts below 200 cells/µL had a LE of 5.7 years (95% CI 3.6-8.2). No increase in LE with later calendar period of diagnosis was observed. CONCLUSIONS: LE was shown to be markedly lower among HIV-infected patients compared with the background population. While other settings have shown marked improvements in prognosis of HIV-infected patients in recent years, no improvement in Bissau was observed over time (9.8 years (95% CI 7.6-12.2) and 9.9 years (95% CI 7.6-12.1) for the periods 2005-2010 and 2014-2016, respectively).

HIV-1 and HIV-2 prevalence, risk factors and birth outcomes among pregnant women in Bissau, Guinea-Bissau: a retrospective cross-sectional hospital study.

The human immunodeficiency virus (HIV) remains a leading cause of maternal morbidity and mortality in Sub-Saharan Africa. Prevention of mother-to-child transmission (PMTCT) has proven an effective strategy to end paediatric infections and ensure HIV-infected mothers access treatment. Based on cross-sectional data collected from June 2008 to May 2013, we assessed changes in HIV prevalence, risk factors for HIV, provision of PMTCT antiretroviral treatment (ART), and the association between HIV infection, birth outcomes and maternal characteristics at the Simão Mendes National Hospital, Guinea-Bissau's largest maternity ward. Among 24,107 women, the HIV prevalence was 3.3% for HIV-1, 0.8% for HIV-2 and 0.9% for HIV-1/2. A significant decline in HIV-1, HIV-2, and HIV-1/2 prevalence was observed over time. HIV infection was associated with age and ethnicity. A total of 85% of HIV-infected women received ART as part of PMTCT, yet overall treatment coverage during labour and delivery declined significantly for both mothers and infants. Twenty-two percent of infants did not receive treatment, and 67% of HIV-2-infected mothers and 77% of their infants received ineffective non-nucleoside reverse transcriptase inhibitors for PMTCT. Maternal HIV was associated with low birth weight but not stillbirth. Inadequate continuity of care and ART coverage present challenges to optimal PMTCT in Guinea-Bissau.

Successful use of extracorporeal membrane oxygenation in respiratory failure due to influenza and acute myeloid leukemia.

We report the use of extracorporeal membrane oxygenation (ECMO) in a 28-year-old woman who had an influenza infection complicated with severe acute respiratory distress syndrome (ARDS) during treatment for acute myeloid leukemia. Despite ventilator management with positive end-expiratory pressure, nitrogen oxide inhalation, and prone positioning, there was severe hypoxemia. ECMO led to improvement in gas exchange and lung mechanics. This case shows that ECMO can be lifesaving in the treatment of immunocompromised patients who have hypoxemia that is refractory to conventional treatment.

A clinical score has utility in tuberculosis case-finding among patients with HIV: A feasibility study from Bissau.

BACKGROUND: Clinical scores are promising case-finding tools for tuberculosis (TB) among HIV-infected patients. The Bandim TBscore has been shown to increase the diagnostic yield among patients with presumed TB in general, but has not previously been tested among newly diagnosed HIV patients at high risk of TB. METHODS: HIV-infected patients were included in this cross-sectional study. A pre-post-intervention study design was used to assess the outcome of a change in practice, i.e. the application of a clinical score (TBscore) consisting of 13 signs and symptoms to assess the need for further TB diagnostics. Patients with a TBscore ≥2 were evaluated using smear microscopy and Xpert MTB/RIF. A TB diagnosis was made based on microbiology or clinical evaluation. The sensitivity and specificity of the TBscore were compared with those of World Health Organization symptoms. RESULTS: The TB prevalence among newly enrolled HIV-infected patients during the study period was 13.4% (22/164). Using the TBscore and a diagnostic algorithm, it was possible to increase the proportion of patients started on TB treatment from 2.7% (10/367) the year before the study to 10.4% (17/164) during the study period. Five patients diagnosed with TB were not started on TB treatment as they were lost to follow-up or died. With a cut-off value of 2, the TBscore had a sensitivity, specificity, positive predictive value, and negative predictive value of 95.5% (21/22), 36.9% (41/111), 23.1% (22/118), and 97.6% (41/42), respectively. CONCLUSION: The TBscore is useful for standardized TB screening among HIV-infected individuals and may be a valuable tool to prioritize patients at high risk of TB.

Hepatitis B and C in the adult population of Bissau, Guinea-Bissau: a cross-sectional survey.

OBJECTIVE: Hepatitis B virus (HBV) and hepatitis C virus (HCV) are prevalent in West Africa. To address the WHO 2030 goals of a 90% reduction in incidence and a 65% reduction in mortality for both infections, we assessed the prevalence of HBV and HCV from surveys in the general population. METHODS: Participants in this cross-sectional survey were included from randomly selected houses in a demographic surveillance site in Bissau, Guinea-Bissau. Participants were interviewed and had a blood sample drawn for viral analyses (HBsAg, anti-HBs, anti-HBc, anti-HCV and HCV RNA). Risk factors of HBV and HCV infection were determined by binomial regression adjusted for sex and age. RESULTS: A total of 2715 participants were included in this study. The overall HBsAg prevalence was 18.7% (95% CI: 17.3-20.2%). HBsAg was associated with male sex (adjusted risk ratio (aRR): 1.64), and prevalence decreased with age >34 years. HBV exposure was found in 91.9% of participants. Although 72.6% of individuals without sexual debut had been exposed to HBV, ever engaging in a sexual relationship was associated with higher risk of HBV exposure (aRR 1.18). The anti-HCV prevalence was 0.5% (95% CI: 0.3-0.9%), and 78.6% of those had detectable HCV RNA. Risk factors for anti-HCV sero-positivity were age above 55 (aRR 10.60), a history of blood transfusion (aRR 5.07) and being in a polygamous marriage (aRR 3.52). CONCLUSION: In Guinea-Bissau initiatives to implement treatment and widespread testing are needed to reach the WHO 2030 goals.

OBJECTIF: Le virus de l'hépatite B (VHB) et le virus de l'hépatite C (VHC) sont répandus en Afrique de l'Ouest. Pour atteindre les objectifs de 2030 de l'OMS d'une réduction de 90% de l'incidence et de 65% de la mortalité pour les deux infections, nous avons évalué la prévalence du VHB et du VHC à partir d'enquêtes dans la population générale. MÉTHODES: Les participants inclus dans cette enquête transversale provenaient de foyers sélectionnés au hasard dans un site de surveillance démographique à Bissau, en Guinée-Bissau. Les participants ont été interrogés et ont subi un prélèvement d'échantillon de sang pour des analyses virales (HBsAg, anti-HBs, anti-HBc, anti-HCV et ARN du HCV). Les facteurs de risque d'infection par le VHB et le VHC ont été déterminés par la régression binomiale ajustée en fonction du sexe et de l'âge. RÉSULTATS: 2.715 participants ont été inclus dans cette étude. La prévalence globale de l'HBsAg était de 18,7% (IC95%: 17,3-20,2%). L'HBsAg était associé au sexe masculin (rapport de risque ajusté (aRR): 1,64), et la prévalence diminuait avec l'âge >34 ans. Une exposition au VHB a été observée chez 91,9% des participants. Bien que 72,6% des personnes sans début d'activité sexuelle aient été exposées au VHB, le fait de s'engager dans des relations sexuelles était associé à un risque plus élevé d'exposition au VHB (aRR: 1,18). La prévalence d'anti-VHC était de 0,5% (IC95%: 0,3-0,9%) et 78,6% d'entre eux avaient de l'ARN du VHC détectable. Les facteurs de risque de séropositivité anti-VHC étaient l'âge de plus de 55 ans (aRR: 10,60), les antécédents de transfusion sanguine (aRR: 5,07) et le fait d'être dans un mariage polygame (aRR: 3,52). CONCLUSION: En Guinée-Bissau, des initiatives pour mettre en œuvre un traitement et des tests généralisés sont nécessaires pour atteindre les objectifs de l'OMS 2030.

HTLV infected individuals have increased B-cell activation and proinflammatory regulatory T-cells.

Human T-lymphotropic virus (HTLV) affects the human immune system in many ways, most notably by inducing proliferation of infected CD4 + T cells, but several other cell types are also affected. To characterize the effects of HTLV infection, we analysed blood samples from HTLV-infected individuals by flow cytometry. Samples were collected from visitors at the HIV clinic in Bissau, Guinea-Bissau. These samples were tested for HTLV and HIV, and 199 were analysed by flow cytometry using panels for B cells, T-cell maturation and activation, regulatory T cells (Tregs) and monocytes. CD80+ cell proportions were significantly higher in HTLV infected than in HTLV uninfected in all B cell subsets. Among T cells, there was no change in cell distribution between maturation stages, but a higher CD25+ proportion among Tregs (61.1 % vs 36.3 %, p < 0.001) in HTLV infected than in HTLV uninfected. The level of CD49d on individual cells was also higher (MFI 2734.5 vs 1,041, p < 0.001). In HTLV infected individuals, CD8 + T cells had a lower proportion of CTLA-4+ (2.5 % vs 3.5 %, 0.048) and higher PD1+ proportion on the CD45RO + subset (81.6 % vs 77.1 %, p < 0.001). Together, these findings point toward reduced regulation in HTLV + patients, which leads to immune activation. This study corroborates previous findings and offers new insight into the effects of HTLV by providing a broad flowcytometric analysis of immune cells in HTLV + individuals.

Contribution to differential diagnosis of sarcoidosis and disseminated tuberculosis.

A previously healthy 54-year-old ethnically Danish man was referred to the Department of Infectious Diseases at Aarhus University Hospital after an unexpected detection of Mycobacterium tuberculosis DNA in his lungs. Further examination revealed widespread dissemination of the tuberculosis (TB) to brain, mastoid, urinary and gastrointestinal tract. Thirteen months earlier, the patient was orchiectomised due to recurring inflammation of the right testicle. Three and a half months prior to admission to our department the patient started immunosuppressive therapy with steroids due to radiological and histological findings in the lungs that were interpreted as sarcoidosis (SA). This treatment is likely to be co-responsible for the pronounced dissemination of the TB. The patient was Bacillus Calmette-Guérin (BCG)-vaccinated as a child and had no apparent risk factors for TB apart from travelling in TB-endemic countries until 10 years before falling ill. Screening for latent TB was not performed prior to starting steroid treatment.

Phase-out of smallpox vaccination and the female/male HIV-1 prevalence ratio: an ecological study from Guinea-Bissau.

OBJECTIVE: In Guinea-Bissau, West Africa, we observed that having a smallpox vaccination scar was associated with lower HIV-1 prevalence, more strongly for women than men. If this represents a causal effect, the female/male HIV-1 prevalence ratio would increase for birth cohorts no longer receiving smallpox vaccination due to the phase-out of this vaccine. DESIGN: An ecological design using HIV surveys and information about smallpox vaccination coverage. SETTING: Urban and rural Guinea-Bissau. PARTICIPANTS: Participants in HIV surveys were grouped into an age group with decreasing smallpox vaccination coverage (15-34 years) and an age group with steady smallpox vaccination coverage (≥35 years). INTERVENTIONS: The exposure of interest was the phase-out of the smallpox vaccine in Guinea-Bissau. PRIMARY AND SECONDARY OUTCOME MEASURES: HIV-1 prevalence. RESULTS: At both sites, the female/male HIV-1 prevalence ratio increased by calendar time for the age group with decreasing smallpox vaccination coverage; the combined female/male HIV-1 prevalence ratio among people aged 15-34 years was 1.00 (95% CI 0.17 to 5.99) in 1987-1990, 1.16 (95% CI 0.69 to 1.93) in 1996-1997, 2.32 (95% CI 1.51 to 3.56) in 2006-2007 (p value for no trend=0.04). There was no increase in the female-to-male HIV-1 prevalence ratio for the age group >35 years with steady smallpox vaccination coverage; 1.93 (95% CI 0.40 to 9.25) in 1987-1990, 1.32 (95% CI 0.83 to 2.10) in 1996-1997, 0.81 (95% CI 0.56 to 1.16) in 2006-2007 (p value for no trend=0.07). CONCLUSIONS: Thus, data was compatible with the deduction that the phase-out of smallpox vaccination may have increased the susceptibility to HIV-1 relatively more for women than men. Hence, phasing out smallpox vaccination may have contributed to the global increase in the female/male HIV-1 prevalence ratio among young individuals. Due to the potential fallacies of ecological studies, the results should be interpreted carefully, and this hypothesis needs further assessment. If the hypothesis is true, studies of smallpox vaccination could inform HIV-1 vaccine research.

Discriminatory rapid tests cause HIV-type misclassification-evaluation of three rapid tests using clinical samples from Guinea-Bissau.

BACKGROUND: Discrimination among HIV types is important because HIV-2 is naturally resistant to some of the first-line drugs used in the treatment of HIV-1. We evaluated three assays for HIV-type discriminatory capacity: SD Bioline HIV 1/2 3.0 (Bioline), First Response HIV 1-2-0 Card Test (First Response) and Genie III HIV-1/HIV-2 (Genie III). METHODS: Based on results from the Bioline assay, samples from 239 HIV-infected patients from the Bissau HIV cohort in Guinea-Bissau were retrospectively selected for evaluation. Genie III and First Response were scored by three independent readers and compared with a reference test (INNO-LIA HIV I/II Score) confirmed by HIV RNA as well as DNA detection. RESULTS: The best performing test was Genie III, with an average agreement with the reference test of 93.4%, followed by First Response (86.1%) and Bioline (72.4%). First Response and Bioline were scored with a false high number of HIV-1/2 dual infections. For both First Response and Genie III, there were discrepancies among independent readers, and some tests were scored as HIV non-reactive. CONCLUSIONS: Using these rapid tests with a suboptimal performance will presumably result in a high rate of false HIV-1/2 dual diagnoses, depriving patients of alternative treatment options in cases of treatment failure.

HTLV prevalence is no longer following the decreasing HIV prevalence - 20 years of retroviral surveillance in Guinea-Bissau, West Africa.

BACKGROUND: The HIV-2 and HTLV-1 prevalences in Bissau have followed similar trends in surveys from 1996 and 2006 with HTLV-1 prevalences of 3.6% and 2.3%, respectively. However, following the introduction of antiretroviral treatment (ART) and informative campaigns about HIV, the epidemics may have shifted. To evaluate the current HTLV prevalence and the continued association with HIV, we performed a third survey. METHODS: A cross-sectional survey was performed from November 2014 to February 2016. In total, 2583 participants were interviewed, tested for HIV, and had blood samples collected. Samples were analysed for anti-HTLV using chemiluminescence and immunoblot assays. We calculated the HTLV prevalence for 2016 and examined risk factors for HTLV and associations with HIV using binominal regression. RESULTS: The prevalence of HTLV was 2.8% (71/2583), 1.5% (16/1,089) for men and 3.7% (55/1,494) for women. Old age, female sex, HIV-2 infection and sharing a house with a HTLV- infected person were strong risk factors for HTLV. In contrast to previous studies, we found a non-significant increase in prevalence among the 15-24 year-olds since 2006, supporting ongoing transmission. CONCLUSIONS: The HTLV prevalence in Bissau showed a non-significant increase. We found evidence supporting continuous vertical and horizontal routes of transmissions.